From 43664fa0e778acfb3d830952ef2c25411617f676 Mon Sep 17 00:00:00 2001 From: Daniel YC Lin Date: Sat, 28 Jul 2018 21:53:14 +0800 Subject: porting to julia 0.6.4 --- julia.html.markdown | 84 ++++++++++++++++++++++++++++------------------------- 1 file changed, 45 insertions(+), 39 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 9e28452f..a30871eb 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -3,13 +3,14 @@ language: Julia contributors: - ["Leah Hanson", "http://leahhanson.us"] - ["Pranit Bauva", "http://github.com/pranitbauva1997"] + - ["Daniel YC Lin", "http://github.com/dlintw"] filename: learnjulia.jl --- Julia is a new homoiconic functional language focused on technical computing. While having the full power of homoiconic macros, first-class functions, and low-level control, Julia is as easy to learn and use as Python. -This is based on Julia 0.4. +This is based on Julia 0.6.4 ```ruby @@ -49,7 +50,7 @@ div(5, 2) # => 2 # for a truncated result, use div ~2 # => -3 # bitwise not 3 & 5 # => 1 # bitwise and 2 | 4 # => 6 # bitwise or -2 $ 4 # => 6 # bitwise xor +xor(2, 4) # => 6 # bitwise xor 2 >>> 1 # => 1 # logical shift right 2 >> 1 # => 1 # arithmetic shift right 2 << 1 # => 4 # logical/arithmetic shift left @@ -80,25 +81,33 @@ false 2 < 3 < 2 # => false # Strings are created with " +try "This is a string." +catch ; end # Julia has several types of strings, including ASCIIString and UTF8String. # More on this in the Types section. # Character literals are written with ' +try 'a' +catch ; end # Some strings can be indexed like an array of characters +try "This is a string"[1] # => 'T' # Julia indexes from 1 +catch ; end # However, this is will not work well for UTF8 strings, # so iterating over strings is recommended (map, for loops, etc). # $ can be used for string interpolation: +try "2 + 2 = $(2 + 2)" # => "2 + 2 = 4" +catch ; end # You can put any Julia expression inside the parentheses. # Another way to format strings is the printf macro. -@printf "%d is less than %f" 4.5 5.3 # 4.5 is less than 5.300000 +@printf "%d is less than %f" 4.5 5.3 # 4 is less than 5.300000 # Printing is easy println("I'm Julia. Nice to meet you!") @@ -405,8 +414,8 @@ f_add(x, y) = x + y # => "f (generic function with 1 method)" f_add(3, 4) # => 7 # Function can also return multiple values as tuple -f(x, y) = x + y, x - y -f(3, 4) # => (7, -1) +fn(x, y) = x + y, x - y +fn(3, 4) # => (7, -1) # You can define functions that take a variable number of # positional arguments @@ -543,7 +552,7 @@ sherekhan = typeof(tigger)(5.6,"fire") # => Tiger(5.6,"fire") # The other kind of types is abstract types. # abstract Name -abstract Cat # just a name and point in the type hierarchy +abstract type Cat end # just a name and point in the type hierarchy # Abstract types cannot be instantiated, but can have subtypes. # For example, Number is an abstract type @@ -553,30 +562,28 @@ subtypes(Number) # => 2-element Array{Any,1}: subtypes(Cat) # => 0-element Array{Any,1} # AbstractString, as the name implies, is also an abstract type -subtypes(AbstractString) # 8-element Array{Any,1}: - # Base.SubstitutionString{T<:AbstractString} - # DirectIndexString - # RepString - # RevString{T<:AbstractString} - # RopeString - # SubString{T<:AbstractString} - # UTF16String - # UTF8String - -# Every type has a super type; use the `super` function to get it. +subtypes(AbstractString) # 6-element Array{Union{DataType, UnionAll},1}: + # Base.SubstitutionString + # Base.Test.GenericString + # DirectIndexString + # RevString + # String + # SubString + +# Every type has a super type; use the `supertype` function to get it. typeof(5) # => Int64 -super(Int64) # => Signed -super(Signed) # => Integer -super(Integer) # => Real -super(Real) # => Number -super(Number) # => Any -super(super(Signed)) # => Real -super(Any) # => Any +supertype(Int64) # => Signed +supertype(Signed) # => Integer +supertype(Integer) # => Real +supertype(Real) # => Number +supertype(Number) # => Any +supertype(supertype(Signed)) # => Real +supertype(Any) # => Any # All of these type, except for Int64, are abstract. -typeof("fire") # => ASCIIString -super(ASCIIString) # => DirectIndexString -super(DirectIndexString) # => AbstractString -# Likewise here with ASCIIString +typeof("fire") # => String +supertype(String) # => AbstractString +# Likewise here with String +supertype(DirectIndexString) # => AbstractString # <: is the subtyping operator type Lion <: Cat # Lion is a subtype of Cat @@ -670,23 +677,22 @@ fight(l::Lion,c::Cat) = println("The victorious cat says $(meow(c))") fight(Lion("balooga!"),Panther()) # => prints The victorious cat says grrr try - fight(Panther(),Lion("RAWR")) # => ERROR: no method fight(Panther,Lion) -catch + fight(Panther(),Lion("RAWR")) +catch e + println(e) + # => MethodError(fight, (Panther("green"), Lion("green", "RAWR")), 0x000000000000557b) end # Also let the cat go first fight(c::Cat,l::Lion) = println("The cat beats the Lion") -# => Warning: New definition -# fight(Cat,Lion) at none:1 -# is ambiguous with -# fight(Lion,Cat) at none:2. -# Make sure -# fight(Lion,Lion) -# is defined first. -#fight (generic function with 4 methods) # This warning is because it's unclear which fight will be called in: -fight(Lion("RAR"),Lion("brown","rarrr")) # => prints The victorious cat says rarrr +try + fight(Lion("RAR"),Lion("brown","rarrr")) # => prints The victorious cat says rarrr +catch e + println(e) + # => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")), 0x000000000000557c) +end # The result may be different in other versions of Julia fight(l::Lion,l2::Lion) = println("The lions come to a tie") -- cgit v1.2.3 From e9dd72024cee9805f9d763387d4c848a316a7307 Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Tue, 14 Aug 2018 17:55:26 +0200 Subject: julia update version number --- julia.html.markdown | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index a30871eb..d55a166b 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -2,17 +2,18 @@ language: Julia contributors: - ["Leah Hanson", "http://leahhanson.us"] - - ["Pranit Bauva", "http://github.com/pranitbauva1997"] - - ["Daniel YC Lin", "http://github.com/dlintw"] + - ["Pranit Bauva", "https://github.com/pranitbauva1997"] + - ["Daniel YC Lin", "https://github.com/dlintw"] + - ["Martijn Visser", "https://github.com/visr"] filename: learnjulia.jl --- Julia is a new homoiconic functional language focused on technical computing. While having the full power of homoiconic macros, first-class functions, and low-level control, Julia is as easy to learn and use as Python. -This is based on Julia 0.6.4 +This is based on Julia 1.0.0 -```ruby +```julia # Single line comments start with a hash (pound) symbol. #= Multiline comments can be written @@ -779,6 +780,6 @@ code_native(circle_area, (Float64,)) ## Further Reading -You can get a lot more detail from [The Julia Manual](http://docs.julialang.org/en/latest/#Manual-1) +You can get a lot more detail from the [Julia Documentation](https://docs.julialang.org/) The best place to get help with Julia is the (very friendly) [Discourse forum](https://discourse.julialang.org/). -- cgit v1.2.3 From cf5cc6b76cb3978818dc98feef86f62b1b406e63 Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Tue, 14 Aug 2018 18:00:00 +0200 Subject: autoformat with VS code mostly just spaces between arguments --- julia.html.markdown | 140 ++++++++++++++++++++++++++-------------------------- 1 file changed, 70 insertions(+), 70 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index d55a166b..2e4e7c48 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -31,7 +31,7 @@ This is based on Julia 1.0.0 3 # => 3 (Int64) 3.2 # => 3.2 (Float64) 2 + 1im # => 2 + 1im (Complex{Int64}) -2//3 # => 2//3 (Rational{Int64}) +2 // 3 # => 2//3 (Rational{Int64}) # All of the normal infix operators are available. 1 + 1 # => 2 @@ -41,7 +41,7 @@ This is based on Julia 1.0.0 5 / 2 # => 2.5 # dividing an Int by an Int always results in a Float div(5, 2) # => 2 # for a truncated result, use div 5 \ 35 # => 7.0 -2 ^ 2 # => 4 # power, not bitwise xor +2^2 # => 4 # power, not bitwise xor 12 % 10 # => 2 # Enforce precedence with parentheses @@ -83,7 +83,7 @@ false # Strings are created with " try -"This is a string." + "This is a string." catch ; end # Julia has several types of strings, including ASCIIString and UTF8String. @@ -91,19 +91,19 @@ catch ; end # Character literals are written with ' try -'a' + 'a' catch ; end # Some strings can be indexed like an array of characters try -"This is a string"[1] # => 'T' # Julia indexes from 1 + "This is a string"[1] # => 'T' # Julia indexes from 1 catch ; end # However, this is will not work well for UTF8 strings, # so iterating over strings is recommended (map, for loops, etc). # $ can be used for string interpolation: try -"2 + 2 = $(2 + 2)" # => "2 + 2 = 4" + "2 + 2 = $(2 + 2)" # => "2 + 2 = 4" catch ; end # You can put any Julia expression inside the parentheses. @@ -116,7 +116,7 @@ println("I'm Julia. Nice to meet you!") # String can be compared lexicographically "good" > "bye" # => true "good" == "good" # => true -"1 + 2 = 3" == "1 + 2 = $(1+2)" # => true +"1 + 2 = 3" == "1 + 2 = $(1 + 2)" # => true #################################################### ## 2. Variables and Collections @@ -172,17 +172,17 @@ matrix = [1 2; 3 4] # => 2x2 Int64 Array: [1 2; 3 4] b = Int8[4, 5, 6] # => 3-element Int8 Array: [4, 5, 6] # Add stuff to the end of a list with push! and append! -push!(a,1) # => [1] -push!(a,2) # => [1,2] -push!(a,4) # => [1,2,4] -push!(a,3) # => [1,2,4,3] -append!(a,b) # => [1,2,4,3,4,5,6] +push!(a, 1) # => [1] +push!(a, 2) # => [1,2] +push!(a, 4) # => [1,2,4] +push!(a, 3) # => [1,2,4,3] +append!(a, b) # => [1,2,4,3,4,5,6] # Remove from the end with pop pop!(b) # => 6 and b is now [4,5] # Let's put it back -push!(b,6) # b is now [4,5,6] again. +push!(b, 6) # b is now [4,5,6] again. a[1] # => 1 # remember that Julia indexes from 1, not 0! @@ -192,7 +192,7 @@ a[end] # => 6 # we also have shift and unshift shift!(a) # => 1 and a is now [2,4,3,4,5,6] -unshift!(a,7) # => [7,2,4,3,4,5,6] +unshift!(a, 7) # => [7,2,4,3,4,5,6] # Function names that end in exclamations points indicate that they modify # their argument. @@ -203,7 +203,7 @@ sort!(arr) # => [4,5,6]; arr is now [4,5,6] # Looking out of bounds is a BoundsError try a[0] # => ERROR: BoundsError() in getindex at array.jl:270 - a[end+1] # => ERROR: BoundsError() in getindex at array.jl:270 + a[end + 1] # => ERROR: BoundsError() in getindex at array.jl:270 catch e println(e) end @@ -221,11 +221,11 @@ a[2:end] # => [2, 3, 4, 5] # Remove elements from an array by index with splice! arr = [3,4,5] -splice!(arr,2) # => 4 ; arr is now [3,5] +splice!(arr, 2) # => 4 ; arr is now [3,5] # Concatenate lists with append! b = [1,2,3] -append!(a,b) # Now a is [1, 2, 3, 4, 5, 1, 2, 3] +append!(a, b) # Now a is [1, 2, 3, 4, 5, 1, 2, 3] # Check for existence in a list with in in(1, a) # => true @@ -236,7 +236,7 @@ length(a) # => 8 # Tuples are immutable. tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple. tup[1] # => 1 -try: + try: tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64) catch e println(e) @@ -265,7 +265,7 @@ e, d = d, e # => (5,4) # d is now 5 and e is now 4 empty_dict = Dict() # => Dict{Any,Any}() # You can create a dictionary using a literal -filled_dict = Dict("one"=> 1, "two"=> 2, "three"=> 3) +filled_dict = Dict("one" => 1, "two" => 2, "three" => 3) # => Dict{ASCIIString,Int64} # Look up values with [] @@ -296,8 +296,8 @@ end # Use the get method to avoid that error by providing a default value # get(dictionary,key,default_value) -get(filled_dict,"one",4) # => 1 -get(filled_dict,"four",4) # => 4 +get(filled_dict, "one", 4) # => 1 +get(filled_dict, "four", 4) # => 4 # Use Sets to represent collections of unordered, unique values empty_set = Set() # => Set{Any}() @@ -305,7 +305,7 @@ empty_set = Set() # => Set{Any}() filled_set = Set([1,2,2,3,4]) # => Set{Int64}(1,2,3,4) # Add more values to a set -push!(filled_set,5) # => Set{Int64}(5,4,2,3,1) +push!(filled_set, 5) # => Set{Int64}(5,4,2,3,1) # Check if the values are in the set in(2, filled_set) # => true @@ -315,7 +315,7 @@ in(10, filled_set) # => false other_set = Set([3, 4, 5, 6]) # => Set{Int64}(6,4,5,3) intersect(filled_set, other_set) # => Set{Int64}(3,4,5) union(filled_set, other_set) # => Set{Int64}(1,2,3,4,5,6) -setdiff(Set([1,2,3,4]),Set([2,3,5])) # => Set{Int64}(1,4) +setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set{Int64}(1,4) #################################################### @@ -338,7 +338,7 @@ end # For loops iterate over iterables. # Iterable types include Range, Array, Set, Dict, and AbstractString. -for animal=["dog", "cat", "mouse"] +for animal = ["dog", "cat", "mouse"] println("$animal is a mammal") # You can use $ to interpolate variables or expression into strings end @@ -356,7 +356,7 @@ end # cat is a mammal # mouse is a mammal -for a in Dict("dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal") +for a in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal") println("$(a[1]) is a $(a[2])") end # prints: @@ -364,7 +364,7 @@ end # cat is a mammal # mouse is a mammal -for (k,v) in Dict("dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal") +for (k, v) in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal") println("$k is a $v") end # prints: @@ -386,9 +386,9 @@ end # Handle exceptions with a try/catch block try - error("help") + error("help") catch e - println("caught it $e") + println("caught it $e") end # => caught it ErrorException("help") @@ -426,7 +426,7 @@ function varargs(args...) end # => varargs (generic function with 1 method) -varargs(1,2,3) # => (1,2,3) +varargs(1, 2, 3) # => (1,2,3) # The ... is called a splat. # We just used it in a function definition. @@ -434,18 +434,18 @@ varargs(1,2,3) # => (1,2,3) # where it will splat an Array or Tuple's contents into the argument list. add([5,6]...) # this is equivalent to add(5,6) -x = (5,6) # => (5,6) +x = (5, 6) # => (5,6) add(x...) # this is equivalent to add(5,6) # You can define functions with optional positional arguments -function defaults(a,b,x=5,y=6) +function defaults(a, b, x=5, y=6) return "$a $b and $x $y" end -defaults('h','g') # => "h g and 5 6" -defaults('h','g','j') # => "h g and j 6" -defaults('h','g','j','k') # => "h g and j k" +defaults('h', 'g') # => "h g and 5 6" +defaults('h', 'g', 'j') # => "h g and j 6" +defaults('h', 'g', 'j', 'k') # => "h g and j k" try defaults('h') # => ERROR: no method defaults(Char,) defaults() # => ERROR: no methods defaults() @@ -454,8 +454,8 @@ catch e end # You can define functions that take keyword arguments -function keyword_args(;k1=4,name2="hello") # note the ; - return Dict("k1"=>k1,"name2"=>name2) +function keyword_args(;k1=4, name2="hello") # note the ; + return Dict("k1" => k1, "name2" => name2) end keyword_args(name2="ness") # => ["name2"=>"ness","k1"=>4] @@ -508,7 +508,7 @@ map(add_10, [1,2,3]) # => [11, 12, 13] filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # We can use list comprehensions for nicer maps -[add_10(i) for i=[1, 2, 3]] # => [11, 12, 13] +[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13] [add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] #################################################### @@ -537,16 +537,16 @@ typeof(DataType) # => DataType # ... # end type Tiger - taillength::Float64 - coatcolor # not including a type annotation is the same as `::Any` + taillength::Float64 + coatcolor # not including a type annotation is the same as `::Any` end # The default constructor's arguments are the properties # of the type, in the order they are listed in the definition -tigger = Tiger(3.5,"orange") # => Tiger(3.5,"orange") +tigger = Tiger(3.5, "orange") # => Tiger(3.5,"orange") # The type doubles as the constructor function for values of that type -sherekhan = typeof(tigger)(5.6,"fire") # => Tiger(5.6,"fire") +sherekhan = typeof(tigger)(5.6, "fire") # => Tiger(5.6,"fire") # These struct-style types are called concrete types # They can be instantiated, but cannot have subtypes. @@ -588,19 +588,19 @@ supertype(DirectIndexString) # => AbstractString # <: is the subtyping operator type Lion <: Cat # Lion is a subtype of Cat - mane_color - roar::AbstractString + mane_color + roar::AbstractString end # You can define more constructors for your type # Just define a function of the same name as the type # and call an existing constructor to get a value of the correct type -Lion(roar::AbstractString) = Lion("green",roar) +Lion(roar::AbstractString) = Lion("green", roar) # This is an outer constructor because it's outside the type definition type Panther <: Cat # Panther is also a subtype of Cat - eye_color - Panther() = new("green") + eye_color + Panther() = new("green") # Panthers will only have this constructor, and no default constructor. end # Using inner constructors, like Panther does, gives you control @@ -619,30 +619,30 @@ end # Definitions for Lion, Panther, Tiger function meow(animal::Lion) - animal.roar # access type properties using dot notation + animal.roar # access type properties using dot notation end function meow(animal::Panther) - "grrr" + "grrr" end function meow(animal::Tiger) - "rawwwr" + "rawwwr" end # Testing the meow function meow(tigger) # => "rawwr" -meow(Lion("brown","ROAAR")) # => "ROAAR" +meow(Lion("brown", "ROAAR")) # => "ROAAR" meow(Panther()) # => "grrr" # Review the local type hierarchy -issubtype(Tiger,Cat) # => false -issubtype(Lion,Cat) # => true -issubtype(Panther,Cat) # => true +issubtype(Tiger, Cat) # => false +issubtype(Lion, Cat) # => true +issubtype(Panther, Cat) # => true # Defining a function that takes Cats function pet_cat(cat::Cat) - println("The cat says $(meow(cat))") + println("The cat says $(meow(cat))") end pet_cat(Lion("42")) # => prints "The cat says 42" @@ -657,47 +657,47 @@ end # In Julia, all of the argument types contribute to selecting the best method. # Let's define a function with more arguments, so we can see the difference -function fight(t::Tiger,c::Cat) - println("The $(t.coatcolor) tiger wins!") +function fight(t::Tiger, c::Cat) + println("The $(t.coatcolor) tiger wins!") end # => fight (generic function with 1 method) -fight(tigger,Panther()) # => prints The orange tiger wins! -fight(tigger,Lion("ROAR")) # => prints The orange tiger wins! +fight(tigger, Panther()) # => prints The orange tiger wins! +fight(tigger, Lion("ROAR")) # => prints The orange tiger wins! # Let's change the behavior when the Cat is specifically a Lion -fight(t::Tiger,l::Lion) = println("The $(l.mane_color)-maned lion wins!") +fight(t::Tiger, l::Lion) = println("The $(l.mane_color)-maned lion wins!") # => fight (generic function with 2 methods) -fight(tigger,Panther()) # => prints The orange tiger wins! -fight(tigger,Lion("ROAR")) # => prints The green-maned lion wins! +fight(tigger, Panther()) # => prints The orange tiger wins! +fight(tigger, Lion("ROAR")) # => prints The green-maned lion wins! # We don't need a Tiger in order to fight -fight(l::Lion,c::Cat) = println("The victorious cat says $(meow(c))") +fight(l::Lion, c::Cat) = println("The victorious cat says $(meow(c))") # => fight (generic function with 3 methods) -fight(Lion("balooga!"),Panther()) # => prints The victorious cat says grrr +fight(Lion("balooga!"), Panther()) # => prints The victorious cat says grrr try - fight(Panther(),Lion("RAWR")) + fight(Panther(), Lion("RAWR")) catch e - println(e) + println(e) # => MethodError(fight, (Panther("green"), Lion("green", "RAWR")), 0x000000000000557b) end # Also let the cat go first -fight(c::Cat,l::Lion) = println("The cat beats the Lion") +fight(c::Cat, l::Lion) = println("The cat beats the Lion") # This warning is because it's unclear which fight will be called in: try - fight(Lion("RAR"),Lion("brown","rarrr")) # => prints The victorious cat says rarrr + fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The victorious cat says rarrr catch e - println(e) + println(e) # => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")), 0x000000000000557c) end # The result may be different in other versions of Julia -fight(l::Lion,l2::Lion) = println("The lions come to a tie") -fight(Lion("RAR"),Lion("brown","rarrr")) # => prints The lions come to a tie +fight(l::Lion, l2::Lion) = println("The lions come to a tie") +fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The lions come to a tie # Under the hood -- cgit v1.2.3 From 031d9d75c4d07b9e3c6007c23f7b331a08d32796 Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Tue, 14 Aug 2018 19:01:13 +0200 Subject: double space before comments not part of official style guide, but i think it more clearly separates code and comment --- julia.html.markdown | 102 ++++++++++++++++++++++++++-------------------------- 1 file changed, 51 insertions(+), 51 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 2e4e7c48..c92434ff 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -28,33 +28,33 @@ This is based on Julia 1.0.0 # Everything in Julia is an expression. # There are several basic types of numbers. -3 # => 3 (Int64) -3.2 # => 3.2 (Float64) -2 + 1im # => 2 + 1im (Complex{Int64}) -2 // 3 # => 2//3 (Rational{Int64}) +3 # => 3 (Int64) +3.2 # => 3.2 (Float64) +2 + 1im # => 2 + 1im (Complex{Int64}) +2 // 3 # => 2//3 (Rational{Int64}) # All of the normal infix operators are available. -1 + 1 # => 2 -8 - 1 # => 7 -10 * 2 # => 20 -35 / 5 # => 7.0 -5 / 2 # => 2.5 # dividing an Int by an Int always results in a Float -div(5, 2) # => 2 # for a truncated result, use div -5 \ 35 # => 7.0 -2^2 # => 4 # power, not bitwise xor -12 % 10 # => 2 +1 + 1 # => 2 +8 - 1 # => 7 +10 * 2 # => 20 +35 / 5 # => 7.0 +5 / 2 # => 2.5 # dividing an Int by an Int always results in a Float +div(5, 2) # => 2 # for a truncated result, use div +5 \ 35 # => 7.0 +2^2 # => 4 # power, not bitwise xor +12 % 10 # => 2 # Enforce precedence with parentheses -(1 + 3) * 2 # => 8 +(1 + 3) * 2 # => 8 # Bitwise Operators -~2 # => -3 # bitwise not -3 & 5 # => 1 # bitwise and -2 | 4 # => 6 # bitwise or -xor(2, 4) # => 6 # bitwise xor -2 >>> 1 # => 1 # logical shift right -2 >> 1 # => 1 # arithmetic shift right -2 << 1 # => 4 # logical/arithmetic shift left +~2 # => -3 # bitwise not +3 & 5 # => 1 # bitwise and +2 | 4 # => 6 # bitwise or +xor(2, 4) # => 6 # bitwise xor +2 >>> 1 # => 1 # logical shift right +2 >> 1 # => 1 # arithmetic shift right +2 << 1 # => 4 # logical/arithmetic shift left # You can use the bits function to see the binary representation of a number. bits(12345) @@ -67,19 +67,19 @@ true false # Boolean operators -!true # => false -!false # => true -1 == 1 # => true -2 == 1 # => false -1 != 1 # => false -2 != 1 # => true -1 < 10 # => true -1 > 10 # => false -2 <= 2 # => true -2 >= 2 # => true +!true # => false +!false # => true +1 == 1 # => true +2 == 1 # => false +1 != 1 # => false +2 != 1 # => true +1 < 10 # => true +1 > 10 # => false +2 <= 2 # => true +2 >= 2 # => true # Comparisons can be chained -1 < 2 < 3 # => true -2 < 3 < 2 # => false +1 < 2 < 3 # => true +2 < 3 < 2 # => false # Strings are created with " try @@ -108,7 +108,7 @@ catch ; end # You can put any Julia expression inside the parentheses. # Another way to format strings is the printf macro. -@printf "%d is less than %f" 4.5 5.3 # 4 is less than 5.300000 +@printf "%d is less than %f" 4.5 5.3 # 4 is less than 5.300000 # Printing is easy println("I'm Julia. Nice to meet you!") @@ -123,22 +123,22 @@ println("I'm Julia. Nice to meet you!") #################################################### # You don't declare variables before assigning to them. -some_var = 5 # => 5 -some_var # => 5 +some_var = 5 # => 5 +some_var # => 5 # Accessing a previously unassigned variable is an error try - some_other_var # => ERROR: some_other_var not defined + some_other_var # => ERROR: some_other_var not defined catch e println(e) end # Variable names start with a letter or underscore. # After that, you can use letters, digits, underscores, and exclamation points. -SomeOtherVar123! = 6 # => 6 +SomeOtherVar123! = 6 # => 6 # You can also use certain unicode characters -☃ = 8 # => 8 +☃ = 8 # => 8 # These are especially handy for mathematical notation 2 * π # => 6.283185307179586 @@ -184,7 +184,7 @@ pop!(b) # => 6 and b is now [4,5] # Let's put it back push!(b, 6) # b is now [4,5,6] again. -a[1] # => 1 # remember that Julia indexes from 1, not 0! +a[1] # => 1 # remember that Julia indexes from 1, not 0! # end is a shorthand for the last index. It can be used in any # indexing expression @@ -237,7 +237,7 @@ length(a) # => 8 tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple. tup[1] # => 1 try: - tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64) + tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64) catch e println(e) end @@ -251,11 +251,11 @@ in(2, tup) # => true a, b, c = (1, 2, 3) # => (1,2,3) # a is now 1, b is now 2 and c is now 3 # Tuples are created even if you leave out the parentheses -d, e, f = 4, 5, 6 # => (4,5,6) +d, e, f = 4, 5, 6 # => (4,5,6) # A 1-element tuple is distinct from the value it contains -(1,) == 1 # => false -(1) == 1 # => true +(1,) == 1 # => false +(1) == 1 # => true # Look how easy it is to swap two values e, d = d, e # => (5,4) # d is now 5 and e is now 4 @@ -411,7 +411,7 @@ end add(5, 6) # => 11 after printing out "x is 5 and y is 6" # Compact assignment of functions -f_add(x, y) = x + y # => "f (generic function with 1 method)" +f_add(x, y) = x + y # => "f (generic function with 1 method)" f_add(3, 4) # => 7 # Function can also return multiple values as tuple @@ -538,7 +538,7 @@ typeof(DataType) # => DataType # end type Tiger taillength::Float64 - coatcolor # not including a type annotation is the same as `::Any` + coatcolor # not including a type annotation is the same as `::Any` end # The default constructor's arguments are the properties @@ -553,7 +553,7 @@ sherekhan = typeof(tigger)(5.6, "fire") # => Tiger(5.6,"fire") # The other kind of types is abstract types. # abstract Name -abstract type Cat end # just a name and point in the type hierarchy +abstract type Cat end # just a name and point in the type hierarchy # Abstract types cannot be instantiated, but can have subtypes. # For example, Number is an abstract type @@ -587,7 +587,7 @@ supertype(String) # => AbstractString supertype(DirectIndexString) # => AbstractString # <: is the subtyping operator -type Lion <: Cat # Lion is a subtype of Cat +type Lion <: Cat # Lion is a subtype of Cat mane_color roar::AbstractString end @@ -598,7 +598,7 @@ end Lion(roar::AbstractString) = Lion("green", roar) # This is an outer constructor because it's outside the type definition -type Panther <: Cat # Panther is also a subtype of Cat +type Panther <: Cat # Panther is also a subtype of Cat eye_color Panther() = new("green") # Panthers will only have this constructor, and no default constructor. @@ -619,7 +619,7 @@ end # Definitions for Lion, Panther, Tiger function meow(animal::Lion) - animal.roar # access type properties using dot notation + animal.roar # access type properties using dot notation end function meow(animal::Panther) @@ -738,7 +738,7 @@ code_native(square_area, (Float64,)) # push RBP # mov RBP, RSP # Source line: 1 - # vmulsd XMM0, XMM0, XMM0 # Scalar double precision multiply (AVX) + # vmulsd XMM0, XMM0, XMM0 # Scalar double precision multiply (AVX) # pop RBP # ret # -- cgit v1.2.3 From e18bab117b34f34d7909474928f8d0a713b8df15 Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Tue, 14 Aug 2018 19:05:54 +0200 Subject: replace tabs with 4 spaces --- julia.html.markdown | 120 ++++++++++++++++++++++++++-------------------------- 1 file changed, 60 insertions(+), 60 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index c92434ff..6964c6c6 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -564,12 +564,12 @@ subtypes(Cat) # => 0-element Array{Any,1} # AbstractString, as the name implies, is also an abstract type subtypes(AbstractString) # 6-element Array{Union{DataType, UnionAll},1}: - # Base.SubstitutionString - # Base.Test.GenericString - # DirectIndexString - # RevString - # String - # SubString + # Base.SubstitutionString + # Base.Test.GenericString + # DirectIndexString + # RevString + # String + # SubString # Every type has a super type; use the `supertype` function to get it. typeof(5) # => Int64 @@ -709,39 +709,39 @@ square_area(5) #25 # What happens when we feed square_area an integer? code_native(square_area, (Int32,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 # Prologue - # push RBP - # mov RBP, RSP - # Source line: 1 - # movsxd RAX, EDI # Fetch l from memory? - # imul RAX, RAX # Square l and store the result in RAX - # pop RBP # Restore old base pointer - # ret # Result will still be in RAX + # .section __TEXT,__text,regular,pure_instructions + # Filename: none + # Source line: 1 # Prologue + # push RBP + # mov RBP, RSP + # Source line: 1 + # movsxd RAX, EDI # Fetch l from memory? + # imul RAX, RAX # Square l and store the result in RAX + # pop RBP # Restore old base pointer + # ret # Result will still be in RAX code_native(square_area, (Float32,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 - # push RBP - # mov RBP, RSP - # Source line: 1 - # vmulss XMM0, XMM0, XMM0 # Scalar single precision multiply (AVX) - # pop RBP - # ret + # .section __TEXT,__text,regular,pure_instructions + # Filename: none + # Source line: 1 + # push RBP + # mov RBP, RSP + # Source line: 1 + # vmulss XMM0, XMM0, XMM0 # Scalar single precision multiply (AVX) + # pop RBP + # ret code_native(square_area, (Float64,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 - # push RBP - # mov RBP, RSP - # Source line: 1 - # vmulsd XMM0, XMM0, XMM0 # Scalar double precision multiply (AVX) - # pop RBP - # ret - # + # .section __TEXT,__text,regular,pure_instructions + # Filename: none + # Source line: 1 + # push RBP + # mov RBP, RSP + # Source line: 1 + # vmulsd XMM0, XMM0, XMM0 # Scalar double precision multiply (AVX) + # pop RBP + # ret + # # Note that julia will use floating point instructions if any of the # arguments are floats. # Let's calculate the area of a circle @@ -749,33 +749,33 @@ circle_area(r) = pi * r * r # circle_area (generic function with 1 method) circle_area(5) # 78.53981633974483 code_native(circle_area, (Int32,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 - # push RBP - # mov RBP, RSP - # Source line: 1 - # vcvtsi2sd XMM0, XMM0, EDI # Load integer (r) from memory - # movabs RAX, 4593140240 # Load pi - # vmulsd XMM1, XMM0, QWORD PTR [RAX] # pi * r - # vmulsd XMM0, XMM0, XMM1 # (pi * r) * r - # pop RBP - # ret - # + # .section __TEXT,__text,regular,pure_instructions + # Filename: none + # Source line: 1 + # push RBP + # mov RBP, RSP + # Source line: 1 + # vcvtsi2sd XMM0, XMM0, EDI # Load integer (r) from memory + # movabs RAX, 4593140240 # Load pi + # vmulsd XMM1, XMM0, QWORD PTR [RAX] # pi * r + # vmulsd XMM0, XMM0, XMM1 # (pi * r) * r + # pop RBP + # ret + # code_native(circle_area, (Float64,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 - # push RBP - # mov RBP, RSP - # movabs RAX, 4593140496 - # Source line: 1 - # vmulsd XMM1, XMM0, QWORD PTR [RAX] - # vmulsd XMM0, XMM1, XMM0 - # pop RBP - # ret - # + # .section __TEXT,__text,regular,pure_instructions + # Filename: none + # Source line: 1 + # push RBP + # mov RBP, RSP + # movabs RAX, 4593140496 + # Source line: 1 + # vmulsd XMM1, XMM0, QWORD PTR [RAX] + # vmulsd XMM0, XMM1, XMM0 + # pop RBP + # ret + # ``` ## Further Reading -- cgit v1.2.3 From 912a51c8ba87cfea5c9eb0c3285636e91e7c0720 Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Tue, 14 Aug 2018 19:08:01 +0200 Subject: remove some trailing spaces --- julia.html.markdown | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 6964c6c6..8cbe3d5e 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -566,9 +566,9 @@ subtypes(Cat) # => 0-element Array{Any,1} subtypes(AbstractString) # 6-element Array{Union{DataType, UnionAll},1}: # Base.SubstitutionString # Base.Test.GenericString - # DirectIndexString - # RevString - # String + # DirectIndexString + # RevString + # String # SubString # Every type has a super type; use the `supertype` function to get it. @@ -680,7 +680,7 @@ fight(Lion("balooga!"), Panther()) # => prints The victorious cat says grrr try fight(Panther(), Lion("RAWR")) catch e - println(e) + println(e) # => MethodError(fight, (Panther("green"), Lion("green", "RAWR")), 0x000000000000557b) end -- cgit v1.2.3 From 876e413558f84d195be625b5c94081c7b6cf6192 Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Tue, 14 Aug 2018 22:19:14 +0200 Subject: fix julia 0.7 deprecation warnings --- julia.html.markdown | 63 +++++++++++++++++++++++++++-------------------------- 1 file changed, 32 insertions(+), 31 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 8cbe3d5e..30aeefc2 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -56,10 +56,10 @@ xor(2, 4) # => 6 # bitwise xor 2 >> 1 # => 1 # arithmetic shift right 2 << 1 # => 4 # logical/arithmetic shift left -# You can use the bits function to see the binary representation of a number. -bits(12345) +# You can use the bitstring function to see the binary representation of a number. +bitstring(12345) # => "0000000000000000000000000000000000000000000000000011000000111001" -bits(12345.0) +bitstring(12345.0) # => "0100000011001000000111001000000000000000000000000000000000000000" # Boolean values are primitives @@ -107,8 +107,9 @@ try catch ; end # You can put any Julia expression inside the parentheses. -# Another way to format strings is the printf macro. -@printf "%d is less than %f" 4.5 5.3 # 4 is less than 5.300000 +# Another way to format strings is the printf macro from the stdlib Printf. +using Printf +@printf "%d is less than %f\n" 4.5 5.3 # => 5 is less than 5.300000 # Printing is easy println("I'm Julia. Nice to meet you!") @@ -128,7 +129,7 @@ some_var # => 5 # Accessing a previously unassigned variable is an error try - some_other_var # => ERROR: some_other_var not defined + some_other_var # => ERROR: UndefVarError: some_other_var not defined catch e println(e) end @@ -190,9 +191,9 @@ a[1] # => 1 # remember that Julia indexes from 1, not 0! # indexing expression a[end] # => 6 -# we also have shift and unshift -shift!(a) # => 1 and a is now [2,4,3,4,5,6] -unshift!(a, 7) # => [7,2,4,3,4,5,6] +# we also have popfirst! and pushfirst! +popfirst!(a) # => 1 and a is now [2,4,3,4,5,6] +pushfirst!(a, 7) # => [7,2,4,3,4,5,6] # Function names that end in exclamations points indicate that they modify # their argument. @@ -236,7 +237,7 @@ length(a) # => 8 # Tuples are immutable. tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple. tup[1] # => 1 - try: +try tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64) catch e println(e) @@ -373,10 +374,11 @@ end # mouse is a mammal # While loops loop while a condition is true -x = 0 -while x < 4 - println(x) - x += 1 # Shorthand for x = x + 1 +let x = 0 + while x < 4 + println(x) + x += 1 # Shorthand for x = x + 1 + end end # prints: # 0 @@ -530,13 +532,13 @@ typeof(DataType) # => DataType # Users can define types # They are like records or structs in other languages. -# New types are defined using the `type` keyword. +# New types are defined using the `struct` keyword. -# type Name +# struct Name # field::OptionalType # ... # end -type Tiger +struct Tiger taillength::Float64 coatcolor # not including a type annotation is the same as `::Any` end @@ -556,6 +558,7 @@ sherekhan = typeof(tigger)(5.6, "fire") # => Tiger(5.6,"fire") abstract type Cat end # just a name and point in the type hierarchy # Abstract types cannot be instantiated, but can have subtypes. +using InteractiveUtils # defines the subtype and supertype function # For example, Number is an abstract type subtypes(Number) # => 2-element Array{Any,1}: # Complex{T<:Real} @@ -563,13 +566,11 @@ subtypes(Number) # => 2-element Array{Any,1}: subtypes(Cat) # => 0-element Array{Any,1} # AbstractString, as the name implies, is also an abstract type -subtypes(AbstractString) # 6-element Array{Union{DataType, UnionAll},1}: - # Base.SubstitutionString - # Base.Test.GenericString - # DirectIndexString - # RevString - # String - # SubString +subtypes(AbstractString) # 4-element Array{Any,1}: + # String + # SubString + # SubstitutionString + # Test.GenericString # Every type has a super type; use the `supertype` function to get it. typeof(5) # => Int64 @@ -584,10 +585,10 @@ supertype(Any) # => Any typeof("fire") # => String supertype(String) # => AbstractString # Likewise here with String -supertype(DirectIndexString) # => AbstractString +supertype(SubString) # => AbstractString # <: is the subtyping operator -type Lion <: Cat # Lion is a subtype of Cat +struct Lion <: Cat # Lion is a subtype of Cat mane_color roar::AbstractString end @@ -598,10 +599,10 @@ end Lion(roar::AbstractString) = Lion("green", roar) # This is an outer constructor because it's outside the type definition -type Panther <: Cat # Panther is also a subtype of Cat +struct Panther <: Cat # Panther is also a subtype of Cat eye_color Panther() = new("green") - # Panthers will only have this constructor, and no default constructor. + # Panthers will only have this constructor, and no default constructor. end # Using inner constructors, like Panther does, gives you control # over how values of the type can be created. @@ -636,9 +637,9 @@ meow(Lion("brown", "ROAAR")) # => "ROAAR" meow(Panther()) # => "grrr" # Review the local type hierarchy -issubtype(Tiger, Cat) # => false -issubtype(Lion, Cat) # => true -issubtype(Panther, Cat) # => true +Tiger <: Cat # => false +Lion <: Cat # => true +Panther <: Cat # => true # Defining a function that takes Cats function pet_cat(cat::Cat) -- cgit v1.2.3 From 10f50ca2297571a471be4963d1af1a11919627fb Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Tue, 14 Aug 2018 22:20:25 +0200 Subject: no need for credit --- julia.html.markdown | 1 - 1 file changed, 1 deletion(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 30aeefc2..a71870be 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -4,7 +4,6 @@ contributors: - ["Leah Hanson", "http://leahhanson.us"] - ["Pranit Bauva", "https://github.com/pranitbauva1997"] - ["Daniel YC Lin", "https://github.com/dlintw"] - - ["Martijn Visser", "https://github.com/visr"] filename: learnjulia.jl --- -- cgit v1.2.3 From c8ad0d08093d692dc2d2d5edb1133f6c90318f42 Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Tue, 14 Aug 2018 22:30:51 +0200 Subject: more comment spacing --- julia.html.markdown | 212 ++++++++++++++++++++++++++-------------------------- 1 file changed, 106 insertions(+), 106 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index a71870be..e5706062 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -33,27 +33,27 @@ This is based on Julia 1.0.0 2 // 3 # => 2//3 (Rational{Int64}) # All of the normal infix operators are available. -1 + 1 # => 2 -8 - 1 # => 7 -10 * 2 # => 20 -35 / 5 # => 7.0 -5 / 2 # => 2.5 # dividing an Int by an Int always results in a Float -div(5, 2) # => 2 # for a truncated result, use div -5 \ 35 # => 7.0 -2^2 # => 4 # power, not bitwise xor -12 % 10 # => 2 +1 + 1 # => 2 +8 - 1 # => 7 +10 * 2 # => 20 +35 / 5 # => 7.0 +5 / 2 # => 2.5 # dividing integers always results in a Float64 +div(5, 2) # => 2 # for a truncated result, use div +5 \ 35 # => 7.0 +2^2 # => 4 # power, not bitwise xor +12 % 10 # => 2 # Enforce precedence with parentheses (1 + 3) * 2 # => 8 # Bitwise Operators -~2 # => -3 # bitwise not -3 & 5 # => 1 # bitwise and -2 | 4 # => 6 # bitwise or -xor(2, 4) # => 6 # bitwise xor -2 >>> 1 # => 1 # logical shift right -2 >> 1 # => 1 # arithmetic shift right -2 << 1 # => 4 # logical/arithmetic shift left +~2 # => -3 # bitwise not +3 & 5 # => 1 # bitwise and +2 | 4 # => 6 # bitwise or +xor(2, 4) # => 6 # bitwise xor +2 >>> 1 # => 1 # logical shift right +2 >> 1 # => 1 # arithmetic shift right +2 << 1 # => 4 # logical/arithmetic shift left # You can use the bitstring function to see the binary representation of a number. bitstring(12345) @@ -66,7 +66,7 @@ true false # Boolean operators -!true # => false +!true # => false !false # => true 1 == 1 # => true 2 == 1 # => false @@ -172,17 +172,17 @@ matrix = [1 2; 3 4] # => 2x2 Int64 Array: [1 2; 3 4] b = Int8[4, 5, 6] # => 3-element Int8 Array: [4, 5, 6] # Add stuff to the end of a list with push! and append! -push!(a, 1) # => [1] -push!(a, 2) # => [1,2] -push!(a, 4) # => [1,2,4] -push!(a, 3) # => [1,2,4,3] -append!(a, b) # => [1,2,4,3,4,5,6] +push!(a, 1) # => [1] +push!(a, 2) # => [1,2] +push!(a, 4) # => [1,2,4] +push!(a, 3) # => [1,2,4,3] +append!(a, b) # => [1,2,4,3,4,5,6] # Remove from the end with pop -pop!(b) # => 6 and b is now [4,5] +pop!(b) # => 6 and b is now [4,5] # Let's put it back -push!(b, 6) # b is now [4,5,6] again. +push!(b, 6) # b is now [4,5,6] again. a[1] # => 1 # remember that Julia indexes from 1, not 0! @@ -191,14 +191,14 @@ a[1] # => 1 # remember that Julia indexes from 1, not 0! a[end] # => 6 # we also have popfirst! and pushfirst! -popfirst!(a) # => 1 and a is now [2,4,3,4,5,6] -pushfirst!(a, 7) # => [7,2,4,3,4,5,6] +popfirst!(a) # => 1 and a is now [2,4,3,4,5,6] +pushfirst!(a, 7) # => [7,2,4,3,4,5,6] # Function names that end in exclamations points indicate that they modify # their argument. arr = [5,4,6] # => 3-element Int64 Array: [5,4,6] -sort(arr) # => [4,5,6]; arr is still [5,4,6] -sort!(arr) # => [4,5,6]; arr is now [4,5,6] +sort(arr) # => [4,5,6]; arr is still [5,4,6] +sort!(arr) # => [4,5,6]; arr is now [4,5,6] # Looking out of bounds is a BoundsError try @@ -221,20 +221,20 @@ a[2:end] # => [2, 3, 4, 5] # Remove elements from an array by index with splice! arr = [3,4,5] -splice!(arr, 2) # => 4 ; arr is now [3,5] +splice!(arr, 2) # => 4 ; arr is now [3,5] # Concatenate lists with append! b = [1,2,3] -append!(a, b) # Now a is [1, 2, 3, 4, 5, 1, 2, 3] +append!(a, b) # Now a is [1, 2, 3, 4, 5, 1, 2, 3] # Check for existence in a list with in -in(1, a) # => true +in(1, a) # => true # Examine the length with length -length(a) # => 8 +length(a) # => 8 # Tuples are immutable. -tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple. +tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple. tup[1] # => 1 try tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64) @@ -243,12 +243,12 @@ catch e end # Many list functions also work on tuples -length(tup) # => 3 +length(tup) # => 3 tup[1:2] # => (1,2) -in(2, tup) # => true +in(2, tup) # => true # You can unpack tuples into variables -a, b, c = (1, 2, 3) # => (1,2,3) # a is now 1, b is now 2 and c is now 3 +a, b, c = (1, 2, 3) # => (1,2,3) # a is now 1, b is now 2 and c is now 3 # Tuples are created even if you leave out the parentheses d, e, f = 4, 5, 6 # => (4,5,6) @@ -258,11 +258,11 @@ d, e, f = 4, 5, 6 # => (4,5,6) (1) == 1 # => true # Look how easy it is to swap two values -e, d = d, e # => (5,4) # d is now 5 and e is now 4 +e, d = d, e # => (5,4) # d is now 5 and e is now 4 # Dictionaries store mappings -empty_dict = Dict() # => Dict{Any,Any}() +empty_dict = Dict() # => Dict{Any,Any}() # You can create a dictionary using a literal filled_dict = Dict("one" => 1, "two" => 2, "three" => 3) @@ -282,10 +282,10 @@ values(filled_dict) # Note - Same as above regarding key ordering. # Check for existence of keys in a dictionary with in, haskey -in(("one" => 1), filled_dict) # => true -in(("two" => 3), filled_dict) # => false -haskey(filled_dict, "one") # => true -haskey(filled_dict, 1) # => false +in(("one" => 1), filled_dict) # => true +in(("two" => 3), filled_dict) # => false +haskey(filled_dict, "one") # => true +haskey(filled_dict, 1) # => false # Trying to look up a non-existent key will raise an error try @@ -296,26 +296,26 @@ end # Use the get method to avoid that error by providing a default value # get(dictionary,key,default_value) -get(filled_dict, "one", 4) # => 1 -get(filled_dict, "four", 4) # => 4 +get(filled_dict, "one", 4) # => 1 +get(filled_dict, "four", 4) # => 4 # Use Sets to represent collections of unordered, unique values -empty_set = Set() # => Set{Any}() +empty_set = Set() # => Set{Any}() # Initialize a set with values -filled_set = Set([1,2,2,3,4]) # => Set{Int64}(1,2,3,4) +filled_set = Set([1,2,2,3,4]) # => Set{Int64}(1,2,3,4) # Add more values to a set -push!(filled_set, 5) # => Set{Int64}(5,4,2,3,1) +push!(filled_set, 5) # => Set{Int64}(5,4,2,3,1) # Check if the values are in the set -in(2, filled_set) # => true -in(10, filled_set) # => false +in(2, filled_set) # => true +in(10, filled_set) # => false # There are functions for set intersection, union, and difference. -other_set = Set([3, 4, 5, 6]) # => Set{Int64}(6,4,5,3) -intersect(filled_set, other_set) # => Set{Int64}(3,4,5) -union(filled_set, other_set) # => Set{Int64}(1,2,3,4,5,6) -setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set{Int64}(1,4) +other_set = Set([3, 4, 5, 6]) # => Set{Int64}(6,4,5,3) +intersect(filled_set, other_set) # => Set{Int64}(3,4,5) +union(filled_set, other_set) # => Set{Int64}(1,2,3,4,5,6) +setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set{Int64}(1,4) #################################################### @@ -409,15 +409,15 @@ function add(x, y) x + y end -add(5, 6) # => 11 after printing out "x is 5 and y is 6" +add(5, 6) # => 11 after printing out "x is 5 and y is 6" # Compact assignment of functions f_add(x, y) = x + y # => "f (generic function with 1 method)" -f_add(3, 4) # => 7 +f_add(3, 4) # => 7 # Function can also return multiple values as tuple fn(x, y) = x + y, x - y -fn(3, 4) # => (7, -1) +fn(3, 4) # => (7, -1) # You can define functions that take a variable number of # positional arguments @@ -427,16 +427,16 @@ function varargs(args...) end # => varargs (generic function with 1 method) -varargs(1, 2, 3) # => (1,2,3) +varargs(1, 2, 3) # => (1,2,3) # The ... is called a splat. # We just used it in a function definition. # It can also be used in a function call, # where it will splat an Array or Tuple's contents into the argument list. -add([5,6]...) # this is equivalent to add(5,6) +add([5,6]...) # this is equivalent to add(5,6) -x = (5, 6) # => (5,6) -add(x...) # this is equivalent to add(5,6) +x = (5, 6) # => (5,6) +add(x...) # this is equivalent to add(5,6) # You can define functions with optional positional arguments @@ -444,24 +444,24 @@ function defaults(a, b, x=5, y=6) return "$a $b and $x $y" end -defaults('h', 'g') # => "h g and 5 6" -defaults('h', 'g', 'j') # => "h g and j 6" -defaults('h', 'g', 'j', 'k') # => "h g and j k" +defaults('h', 'g') # => "h g and 5 6" +defaults('h', 'g', 'j') # => "h g and j 6" +defaults('h', 'g', 'j', 'k') # => "h g and j k" try - defaults('h') # => ERROR: no method defaults(Char,) - defaults() # => ERROR: no methods defaults() + defaults('h') # => ERROR: no method defaults(Char,) + defaults() # => ERROR: no methods defaults() catch e println(e) end # You can define functions that take keyword arguments -function keyword_args(;k1=4, name2="hello") # note the ; +function keyword_args(;k1=4, name2="hello") # note the ; return Dict("k1" => k1, "name2" => name2) end -keyword_args(name2="ness") # => ["name2"=>"ness","k1"=>4] -keyword_args(k1="mine") # => ["k1"=>"mine","name2"=>"hello"] -keyword_args() # => ["name2"=>"hello","k1"=>4] +keyword_args(name2="ness") # => ["name2"=>"ness","k1"=>4] +keyword_args(k1="mine") # => ["k1"=>"mine","name2"=>"hello"] +keyword_args() # => ["name2"=>"hello","k1"=>4] # You can combine all kinds of arguments in the same function function all_the_args(normal_arg, optional_positional_arg=2; keyword_arg="foo") @@ -485,7 +485,7 @@ function create_adder(x) end # This is "stabby lambda syntax" for creating anonymous functions -(x -> x > 2)(3) # => true +(x -> x > 2)(3) # => true # This function is identical to create_adder implementation above. function create_adder(x) @@ -501,12 +501,12 @@ function create_adder(x) end add_10 = create_adder(10) -add_10(3) # => 13 +add_10(3) # => 13 # There are built-in higher order functions -map(add_10, [1,2,3]) # => [11, 12, 13] -filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] +map(add_10, [1,2,3]) # => [11, 12, 13] +filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # We can use list comprehensions for nicer maps [add_10(i) for i = [1, 2, 3]] # => [11, 12, 13] @@ -519,11 +519,11 @@ filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # Julia has a type system. # Every value has a type; variables do not have types themselves. # You can use the `typeof` function to get the type of a value. -typeof(5) # => Int64 +typeof(5) # => Int64 # Types are first-class values -typeof(Int64) # => DataType -typeof(DataType) # => DataType +typeof(Int64) # => DataType +typeof(DataType) # => DataType # DataType is the type that represents types, including itself. # Types are used for documentation, optimizations, and dispatch. @@ -544,10 +544,10 @@ end # The default constructor's arguments are the properties # of the type, in the order they are listed in the definition -tigger = Tiger(3.5, "orange") # => Tiger(3.5,"orange") +tigger = Tiger(3.5, "orange") # => Tiger(3.5,"orange") # The type doubles as the constructor function for values of that type -sherekhan = typeof(tigger)(5.6, "fire") # => Tiger(5.6,"fire") +sherekhan = typeof(tigger)(5.6, "fire") # => Tiger(5.6,"fire") # These struct-style types are called concrete types # They can be instantiated, but cannot have subtypes. @@ -559,32 +559,32 @@ abstract type Cat end # just a name and point in the type hierarchy # Abstract types cannot be instantiated, but can have subtypes. using InteractiveUtils # defines the subtype and supertype function # For example, Number is an abstract type -subtypes(Number) # => 2-element Array{Any,1}: +subtypes(Number) # => 2-element Array{Any,1}: # Complex{T<:Real} # Real -subtypes(Cat) # => 0-element Array{Any,1} +subtypes(Cat) # => 0-element Array{Any,1} # AbstractString, as the name implies, is also an abstract type -subtypes(AbstractString) # 4-element Array{Any,1}: +subtypes(AbstractString) # 4-element Array{Any,1}: # String # SubString # SubstitutionString # Test.GenericString # Every type has a super type; use the `supertype` function to get it. -typeof(5) # => Int64 -supertype(Int64) # => Signed -supertype(Signed) # => Integer -supertype(Integer) # => Real -supertype(Real) # => Number -supertype(Number) # => Any -supertype(supertype(Signed)) # => Real -supertype(Any) # => Any +typeof(5) # => Int64 +supertype(Int64) # => Signed +supertype(Signed) # => Integer +supertype(Integer) # => Real +supertype(Real) # => Number +supertype(Number) # => Any +supertype(supertype(Signed)) # => Real +supertype(Any) # => Any # All of these type, except for Int64, are abstract. -typeof("fire") # => String -supertype(String) # => AbstractString +typeof("fire") # => String +supertype(String) # => AbstractString # Likewise here with String -supertype(SubString) # => AbstractString +supertype(SubString) # => AbstractString # <: is the subtyping operator struct Lion <: Cat # Lion is a subtype of Cat @@ -631,9 +631,9 @@ function meow(animal::Tiger) end # Testing the meow function -meow(tigger) # => "rawwr" -meow(Lion("brown", "ROAAR")) # => "ROAAR" -meow(Panther()) # => "grrr" +meow(tigger) # => "rawwr" +meow(Lion("brown", "ROAAR")) # => "ROAAR" +meow(Panther()) # => "grrr" # Review the local type hierarchy Tiger <: Cat # => false @@ -645,9 +645,9 @@ function pet_cat(cat::Cat) println("The cat says $(meow(cat))") end -pet_cat(Lion("42")) # => prints "The cat says 42" +pet_cat(Lion("42")) # => prints "The cat says 42" try - pet_cat(tigger) # => ERROR: no method pet_cat(Tiger,) + pet_cat(tigger) # => ERROR: no method pet_cat(Tiger,) catch e println(e) end @@ -662,21 +662,21 @@ function fight(t::Tiger, c::Cat) end # => fight (generic function with 1 method) -fight(tigger, Panther()) # => prints The orange tiger wins! -fight(tigger, Lion("ROAR")) # => prints The orange tiger wins! +fight(tigger, Panther()) # => prints The orange tiger wins! +fight(tigger, Lion("ROAR")) # => prints The orange tiger wins! # Let's change the behavior when the Cat is specifically a Lion fight(t::Tiger, l::Lion) = println("The $(l.mane_color)-maned lion wins!") # => fight (generic function with 2 methods) -fight(tigger, Panther()) # => prints The orange tiger wins! -fight(tigger, Lion("ROAR")) # => prints The green-maned lion wins! +fight(tigger, Panther()) # => prints The orange tiger wins! +fight(tigger, Lion("ROAR")) # => prints The green-maned lion wins! # We don't need a Tiger in order to fight fight(l::Lion, c::Cat) = println("The victorious cat says $(meow(c))") # => fight (generic function with 3 methods) -fight(Lion("balooga!"), Panther()) # => prints The victorious cat says grrr +fight(Lion("balooga!"), Panther()) # => prints The victorious cat says grrr try fight(Panther(), Lion("RAWR")) catch e @@ -689,7 +689,7 @@ fight(c::Cat, l::Lion) = println("The cat beats the Lion") # This warning is because it's unclear which fight will be called in: try - fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The victorious cat says rarrr + fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The victorious cat says rarrr catch e println(e) # => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")), 0x000000000000557c) @@ -697,7 +697,7 @@ end # The result may be different in other versions of Julia fight(l::Lion, l2::Lion) = println("The lions come to a tie") -fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The lions come to a tie +fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The lions come to a tie # Under the hood @@ -705,7 +705,7 @@ fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The lions come to a tie square_area(l) = l * l # square_area (generic function with 1 method) -square_area(5) #25 +square_area(5) #25 # What happens when we feed square_area an integer? code_native(square_area, (Int32,)) @@ -746,7 +746,7 @@ code_native(square_area, (Float64,)) # arguments are floats. # Let's calculate the area of a circle circle_area(r) = pi * r * r # circle_area (generic function with 1 method) -circle_area(5) # 78.53981633974483 +circle_area(5) # 78.53981633974483 code_native(circle_area, (Int32,)) # .section __TEXT,__text,regular,pure_instructions -- cgit v1.2.3 From 9fab30a26a0de8603b19b95055f68af031c906bb Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Wed, 15 Aug 2018 16:54:03 +0200 Subject: one more quick run over the code --- julia.html.markdown | 109 ++++++++++++++++++++++++---------------------------- 1 file changed, 51 insertions(+), 58 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index e5706062..71331818 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -30,7 +30,7 @@ This is based on Julia 1.0.0 3 # => 3 (Int64) 3.2 # => 3.2 (Float64) 2 + 1im # => 2 + 1im (Complex{Int64}) -2 // 3 # => 2//3 (Rational{Int64}) +2 // 3 # => 2 // 3 (Rational{Int64}) # All of the normal infix operators are available. 1 + 1 # => 2 @@ -81,29 +81,18 @@ false 2 < 3 < 2 # => false # Strings are created with " -try - "This is a string." -catch ; end - -# Julia has several types of strings, including ASCIIString and UTF8String. -# More on this in the Types section. +"This is a string." # Character literals are written with ' -try - 'a' -catch ; end +'a' -# Some strings can be indexed like an array of characters -try - "This is a string"[1] # => 'T' # Julia indexes from 1 -catch ; end -# However, this is will not work well for UTF8 strings, -# so iterating over strings is recommended (map, for loops, etc). +# Strings are UTF8 encoded. Only if they contain only ASCII characters can +# they be safely indexed. +ascii("This is a string")[1] # => 'T' # Julia indexes from 1 +# Otherwise, iterating over strings is recommended (map, for loops, etc). # $ can be used for string interpolation: -try - "2 + 2 = $(2 + 2)" # => "2 + 2 = 4" -catch ; end +"2 + 2 = $(2 + 2)" # => "2 + 2 = 4" # You can put any Julia expression inside the parentheses. # Another way to format strings is the printf macro from the stdlib Printf. @@ -157,19 +146,19 @@ SomeOtherVar123! = 6 # => 6 # functions are sometimes called mutating functions or in-place functions. # Arrays store a sequence of values indexed by integers 1 through n: -a = Int64[] # => 0-element Int64 Array +a = Int64[] # => 0-element Int64 Array # 1-dimensional array literals can be written with comma-separated values. -b = [4, 5, 6] # => 3-element Int64 Array: [4, 5, 6] -b = [4; 5; 6] # => 3-element Int64 Array: [4, 5, 6] -b[1] # => 4 -b[end] # => 6 +b = [4, 5, 6] # => 3-element Int64 Array: [4, 5, 6] +b = [4; 5; 6] # => 3-element Int64 Array: [4, 5, 6] +b[1] # => 4 +b[end] # => 6 # 2-dimensional arrays use space-separated values and semicolon-separated rows. -matrix = [1 2; 3 4] # => 2x2 Int64 Array: [1 2; 3 4] +matrix = [1 2; 3 4] # => 2x2 Int64 Array: [1 2; 3 4] -# Arrays of a particular Type -b = Int8[4, 5, 6] # => 3-element Int8 Array: [4, 5, 6] +# Arrays of a particular type +b = Int8[4, 5, 6] # => 3-element Int8 Array: [4, 5, 6] # Add stuff to the end of a list with push! and append! push!(a, 1) # => [1] @@ -184,11 +173,11 @@ pop!(b) # => 6 and b is now [4,5] # Let's put it back push!(b, 6) # b is now [4,5,6] again. -a[1] # => 1 # remember that Julia indexes from 1, not 0! +a[1] # => 1 # remember that Julia indexes from 1, not 0! # end is a shorthand for the last index. It can be used in any # indexing expression -a[end] # => 6 +a[end] # => 6 # we also have popfirst! and pushfirst! popfirst!(a) # => 1 and a is now [2,4,3,4,5,6] @@ -196,28 +185,30 @@ pushfirst!(a, 7) # => [7,2,4,3,4,5,6] # Function names that end in exclamations points indicate that they modify # their argument. -arr = [5,4,6] # => 3-element Int64 Array: [5,4,6] +arr = [5,4,6] # => 3-element Int64 Array: [5,4,6] sort(arr) # => [4,5,6]; arr is still [5,4,6] sort!(arr) # => [4,5,6]; arr is now [4,5,6] # Looking out of bounds is a BoundsError try - a[0] # => ERROR: BoundsError() in getindex at array.jl:270 - a[end + 1] # => ERROR: BoundsError() in getindex at array.jl:270 + a[0] + # => BoundsError: attempt to access 7-element Array{Int64,1} at index [0] + a[end + 1] + # => BoundsError: attempt to access 7-element Array{Int64,1} at index [8] catch e println(e) end # Errors list the line and file they came from, even if it's in the standard -# library. If you built Julia from source, you can look in the folder base -# inside the julia folder to find these files. +# library. You can look in the folder share/julia inside the julia folder to +# find these files. # You can initialize arrays from ranges -a = [1:5;] # => 5-element Int64 Array: [1,2,3,4,5] +a = [1:5;] # => 5-element Int64 Array: [1,2,3,4,5] # You can look at ranges with slice syntax. -a[1:3] # => [1, 2, 3] -a[2:end] # => [2, 3, 4, 5] +a[1:3] # => [1, 2, 3] +a[2:end] # => [2, 3, 4, 5] # Remove elements from an array by index with splice! arr = [3,4,5] @@ -235,16 +226,16 @@ length(a) # => 8 # Tuples are immutable. tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple. -tup[1] # => 1 +tup[1] # => 1 try tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64) catch e println(e) end -# Many list functions also work on tuples +# Many array functions also work on tuples length(tup) # => 3 -tup[1:2] # => (1,2) +tup[1:2] # => (1,2) in(2, tup) # => true # You can unpack tuples into variables @@ -266,19 +257,20 @@ empty_dict = Dict() # => Dict{Any,Any}() # You can create a dictionary using a literal filled_dict = Dict("one" => 1, "two" => 2, "three" => 3) -# => Dict{ASCIIString,Int64} +# => Dict{String,Int64} # Look up values with [] -filled_dict["one"] # => 1 +filled_dict["one"] # => 1 # Get all keys keys(filled_dict) -# => KeyIterator{Dict{ASCIIString,Int64}}(["three"=>3,"one"=>1,"two"=>2]) +# => Base.KeySet for a Dict{String,Int64} with 3 entries. Keys: +# "two", "one", "three" # Note - dictionary keys are not sorted or in the order you inserted them. # Get all values values(filled_dict) -# => ValueIterator{Dict{ASCIIString,Int64}}(["three"=>3,"one"=>1,"two"=>2]) +# => Base.ValueIterator{Dict{String,Int64}} with 3 entries. Values: 2, 1, 3 # Note - Same as above regarding key ordering. # Check for existence of keys in a dictionary with in, haskey @@ -289,33 +281,33 @@ haskey(filled_dict, 1) # => false # Trying to look up a non-existent key will raise an error try - filled_dict["four"] # => ERROR: key not found: four in getindex at dict.jl:489 + filled_dict["four"] # => KeyError: key "four" not found catch e println(e) end # Use the get method to avoid that error by providing a default value -# get(dictionary,key,default_value) +# get(dictionary, key, default_value) get(filled_dict, "one", 4) # => 1 get(filled_dict, "four", 4) # => 4 # Use Sets to represent collections of unordered, unique values empty_set = Set() # => Set{Any}() # Initialize a set with values -filled_set = Set([1,2,2,3,4]) # => Set{Int64}(1,2,3,4) +filled_set = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1]) # Add more values to a set -push!(filled_set, 5) # => Set{Int64}(5,4,2,3,1) +push!(filled_set, 5) # => Set([4, 2, 3, 5, 1]) # Check if the values are in the set in(2, filled_set) # => true in(10, filled_set) # => false # There are functions for set intersection, union, and difference. -other_set = Set([3, 4, 5, 6]) # => Set{Int64}(6,4,5,3) -intersect(filled_set, other_set) # => Set{Int64}(3,4,5) -union(filled_set, other_set) # => Set{Int64}(1,2,3,4,5,6) -setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set{Int64}(1,4) +other_set = Set([3, 4, 5, 6]) # => Set([4, 3, 5, 6]) +intersect(filled_set, other_set) # => Set([4, 3, 5]) +union(filled_set, other_set) # => Set([4, 2, 3, 5, 6, 1]) +setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set([4, 1]) #################################################### @@ -356,8 +348,9 @@ end # cat is a mammal # mouse is a mammal -for a in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal") - println("$(a[1]) is a $(a[2])") +for pair in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal") + from, to = pair + println("$from is a $to") end # prints: # dog is a mammal @@ -509,8 +502,8 @@ map(add_10, [1,2,3]) # => [11, 12, 13] filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # We can use list comprehensions for nicer maps -[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13] -[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] +[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13] +[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] #################################################### ## 5. Types @@ -703,9 +696,9 @@ fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The lions come to a tie # Under the hood # You can take a look at the llvm and the assembly code generated. -square_area(l) = l * l # square_area (generic function with 1 method) +square_area(l) = l * l # square_area (generic function with 1 method) -square_area(5) #25 +square_area(5) # => 25 # What happens when we feed square_area an integer? code_native(square_area, (Int32,)) -- cgit v1.2.3 From 843ba7019323e6e7411cae9d4c0fa83ce98baf92 Mon Sep 17 00:00:00 2001 From: Martijn Visser Date: Wed, 15 Aug 2018 17:00:35 +0200 Subject: wrap lines longer than 80 --- julia.html.markdown | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 71331818..07a051e1 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -55,7 +55,7 @@ xor(2, 4) # => 6 # bitwise xor 2 >> 1 # => 1 # arithmetic shift right 2 << 1 # => 4 # logical/arithmetic shift left -# You can use the bitstring function to see the binary representation of a number. +# Use the bitstring function to see the binary representation of a number. bitstring(12345) # => "0000000000000000000000000000000000000000000000000011000000111001" bitstring(12345.0) @@ -674,7 +674,8 @@ try fight(Panther(), Lion("RAWR")) catch e println(e) - # => MethodError(fight, (Panther("green"), Lion("green", "RAWR")), 0x000000000000557b) + # => MethodError(fight, (Panther("green"), Lion("green", "RAWR")), + # 0x000000000000557b) end # Also let the cat go first @@ -682,10 +683,12 @@ fight(c::Cat, l::Lion) = println("The cat beats the Lion") # This warning is because it's unclear which fight will be called in: try - fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The victorious cat says rarrr + fight(Lion("RAR"), Lion("brown", "rarrr")) + # => prints The victorious cat says rarrr catch e println(e) - # => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")), 0x000000000000557c) + # => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")), + # 0x000000000000557c) end # The result may be different in other versions of Julia -- cgit v1.2.3 From 55d4030e97ff206267bc28e5ee42d2ad07db3143 Mon Sep 17 00:00:00 2001 From: Brian Cleary Date: Thu, 16 Aug 2018 16:36:44 -0700 Subject: add comprehension filter example --- julia.html.markdown | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index a30871eb..047bb538 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -506,9 +506,10 @@ add_10(3) # => 13 map(add_10, [1,2,3]) # => [11, 12, 13] filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] -# We can use list comprehensions for nicer maps +# We can use list comprehensions [add_10(i) for i=[1, 2, 3]] # => [11, 12, 13] [add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] +[x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7] #################################################### ## 5. Types -- cgit v1.2.3 From e1ab28f4fab138e7968041190a64ef0dc0a346a4 Mon Sep 17 00:00:00 2001 From: 0u0 Date: Wed, 29 Aug 2018 15:48:40 +0800 Subject: Keep a line 80 chars --- julia.html.markdown | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 891a0a00..0b28d869 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -8,7 +8,8 @@ filename: learnjulia.jl --- Julia is a new homoiconic functional language focused on technical computing. -While having the full power of homoiconic macros, first-class functions, and low-level control, Julia is as easy to learn and use as Python. +While having the full power of homoiconic macros, first-class functions, +and low-level control, Julia is as easy to learn and use as Python. This is based on Julia 1.0.0 -- cgit v1.2.3 From 35215e4a2db7063f105eb30eb19cbf7b9d370cec Mon Sep 17 00:00:00 2001 From: 0u0 Date: Wed, 29 Aug 2018 15:55:04 +0800 Subject: Use more clearly example --- julia.html.markdown | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 0b28d869..dfa3103c 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -28,17 +28,17 @@ This is based on Julia 1.0.0 # Everything in Julia is an expression. # There are several basic types of numbers. -3 # => 3 (Int64) -3.2 # => 3.2 (Float64) -2 + 1im # => 2 + 1im (Complex{Int64}) -2 // 3 # => 2 // 3 (Rational{Int64}) +typeof(3) # => Int64 +typeof(3.2) # => Float64 +typeof(2 + 1im) # => Complex{Int64} +typeof(2 // 3) # => Rational{Int64} # All of the normal infix operators are available. 1 + 1 # => 2 8 - 1 # => 7 10 * 2 # => 20 35 / 5 # => 7.0 -5 / 2 # => 2.5 # dividing integers always results in a Float64 +10 / 2 # => 5.0 # dividing integers always results in a Float64 div(5, 2) # => 2 # for a truncated result, use div 5 \ 35 # => 7.0 2^2 # => 4 # power, not bitwise xor -- cgit v1.2.3 From 5691fb7a8d824a879a8d4391a93c50f27be1ec25 Mon Sep 17 00:00:00 2001 From: 0u0 Date: Fri, 31 Aug 2018 09:43:02 +0800 Subject: Update output for Julia 1.0 --- julia.html.markdown | 317 ++++++++++++++++++++++++++++++++-------------------- 1 file changed, 194 insertions(+), 123 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index dfa3103c..416f1a5a 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -89,7 +89,9 @@ false # Strings are UTF8 encoded. Only if they contain only ASCII characters can # they be safely indexed. -ascii("This is a string")[1] # => 'T' # Julia indexes from 1 +ascii("This is a string")[1] +# => 'T': ASCII/Unicode U+0054 (category Lu: Letter, uppercase) +# Julia indexes from 1 # Otherwise, iterating over strings is recommended (map, for loops, etc). # $ can be used for string interpolation: @@ -101,7 +103,7 @@ using Printf @printf "%d is less than %f\n" 4.5 5.3 # => 5 is less than 5.300000 # Printing is easy -println("I'm Julia. Nice to meet you!") +println("I'm Julia. Nice to meet you!") # => I'm Julia. Nice to meet you! # String can be compared lexicographically "good" > "bye" # => true @@ -147,19 +149,18 @@ SomeOtherVar123! = 6 # => 6 # functions are sometimes called mutating functions or in-place functions. # Arrays store a sequence of values indexed by integers 1 through n: -a = Int64[] # => 0-element Int64 Array +a = Int64[] # => 0-element Array{Int64,1} # 1-dimensional array literals can be written with comma-separated values. -b = [4, 5, 6] # => 3-element Int64 Array: [4, 5, 6] -b = [4; 5; 6] # => 3-element Int64 Array: [4, 5, 6] -b[1] # => 4 +b = [4, 5, 6] # => 3-element Array{Int64,1}: [4, 5, 6] +b = [4; 5; 6] # => 3-element Array{Int64,1}: [4, 5, 6] b[end] # => 6 # 2-dimensional arrays use space-separated values and semicolon-separated rows. -matrix = [1 2; 3 4] # => 2x2 Int64 Array: [1 2; 3 4] +matrix = [1 2; 3 4] # => 2×2 Array{Int64,2}: [1 2; 3 4] # Arrays of a particular type -b = Int8[4, 5, 6] # => 3-element Int8 Array: [4, 5, 6] +b = Int8[4, 5, 6] # => 3-element Array{Int8,1}: [4, 5, 6] # Add stuff to the end of a list with push! and append! push!(a, 1) # => [1] @@ -186,16 +187,28 @@ pushfirst!(a, 7) # => [7,2,4,3,4,5,6] # Function names that end in exclamations points indicate that they modify # their argument. -arr = [5,4,6] # => 3-element Int64 Array: [5,4,6] sort(arr) # => [4,5,6]; arr is still [5,4,6] sort!(arr) # => [4,5,6]; arr is now [4,5,6] +arr = [5,4,6] # => 3-element Array{Int64,1}: [5,4,6] # Looking out of bounds is a BoundsError try - a[0] - # => BoundsError: attempt to access 7-element Array{Int64,1} at index [0] - a[end + 1] - # => BoundsError: attempt to access 7-element Array{Int64,1} at index [8] + a[0] + # => ERROR: BoundsError: attempt to access 7-element Array{Int64,1} at + # index [0] + # => Stacktrace: + # => [1] getindex(::Array{Int64,1}, ::Int64) at .\array.jl:731 + # => [2] top-level scope at none:0 + # => [3] ... + # => in expression starting at ...\LearnJulia.jl:180 + a[end + 1] + # => ERROR: BoundsError: attempt to access 7-element Array{Int64,1} at + # index [8] + # => Stacktrace: + # => [1] getindex(::Array{Int64,1}, ::Int64) at .\array.jl:731 + # => [2] top-level scope at none:0 + # => [3] ... + # => in expression starting at ...\LearnJulia.jl:188 catch e println(e) end @@ -205,7 +218,8 @@ end # find these files. # You can initialize arrays from ranges -a = [1:5;] # => 5-element Int64 Array: [1,2,3,4,5] +a = [1:5;] # => 5-element Array{Int64,1}: [1,2,3,4,5] +a2 = [1:5] # => 1-element Array{UnitRange{Int64},1}: [1:5] # You can look at ranges with slice syntax. a[1:3] # => [1, 2, 3] @@ -229,7 +243,9 @@ length(a) # => 8 tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple. tup[1] # => 1 try - tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64) + tup[1] = 3 + # => ERROR: MethodError: no method matching + # setindex!(::Tuple{Int64,Int64,Int64}, ::Int64, ::Int64) catch e println(e) end @@ -254,11 +270,12 @@ e, d = d, e # => (5,4) # d is now 5 and e is now 4 # Dictionaries store mappings -empty_dict = Dict() # => Dict{Any,Any}() +empty_dict = Dict() # => Dict{Any,Any} with 0 entries # You can create a dictionary using a literal filled_dict = Dict("one" => 1, "two" => 2, "three" => 3) -# => Dict{String,Int64} +# => Dict{String,Int64} with 3 entries: +# => "two" => 2, "one" => 1, "three" => 3 # Look up values with [] filled_dict["one"] # => 1 @@ -266,12 +283,13 @@ filled_dict["one"] # => 1 # Get all keys keys(filled_dict) # => Base.KeySet for a Dict{String,Int64} with 3 entries. Keys: -# "two", "one", "three" +# => "two", "one", "three" # Note - dictionary keys are not sorted or in the order you inserted them. # Get all values values(filled_dict) -# => Base.ValueIterator{Dict{String,Int64}} with 3 entries. Values: 2, 1, 3 +# => Base.ValueIterator for a Dict{String,Int64} with 3 entries. Values: +# => 2, 1, 3 # Note - Same as above regarding key ordering. # Check for existence of keys in a dictionary with in, haskey @@ -282,7 +300,7 @@ haskey(filled_dict, 1) # => false # Trying to look up a non-existent key will raise an error try - filled_dict["four"] # => KeyError: key "four" not found + filled_dict["four"] # => ERROR: KeyError: key "four" not found catch e println(e) end @@ -293,7 +311,7 @@ get(filled_dict, "one", 4) # => 1 get(filled_dict, "four", 4) # => 4 # Use Sets to represent collections of unordered, unique values -empty_set = Set() # => Set{Any}() +empty_set = Set() # => Set(Any[]) # Initialize a set with values filled_set = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1]) @@ -353,18 +371,16 @@ for pair in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal") from, to = pair println("$from is a $to") end -# prints: -# dog is a mammal -# cat is a mammal -# mouse is a mammal +# => mouse is a mammal +# => cat is a mammal +# => dog is a mammal for (k, v) in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal") println("$k is a $v") end -# prints: -# dog is a mammal -# cat is a mammal -# mouse is a mammal +# => mouse is a mammal +# => cat is a mammal +# => dog is a mammal # While loops loop while a condition is true let x = 0 @@ -406,11 +422,11 @@ end add(5, 6) # => 11 after printing out "x is 5 and y is 6" # Compact assignment of functions -f_add(x, y) = x + y # => "f (generic function with 1 method)" +f_add(x, y) = x + y # => f_add (generic function with 1 method) f_add(3, 4) # => 7 # Function can also return multiple values as tuple -fn(x, y) = x + y, x - y +fn(x, y) = x + y, x - y # => fn (generic function with 1 method) fn(3, 4) # => (7, -1) # You can define functions that take a variable number of @@ -437,13 +453,14 @@ add(x...) # this is equivalent to add(5,6) function defaults(a, b, x=5, y=6) return "$a $b and $x $y" end +# => defaults (generic function with 3 methods) defaults('h', 'g') # => "h g and 5 6" defaults('h', 'g', 'j') # => "h g and j 6" defaults('h', 'g', 'j', 'k') # => "h g and j k" try - defaults('h') # => ERROR: no method defaults(Char,) - defaults() # => ERROR: no methods defaults() + defaults('h') # => ERROR: MethodError: no method matching defaults(::Char) + defaults() # => ERROR: MethodError: no method matching defaults() catch e println(e) end @@ -452,10 +469,11 @@ end function keyword_args(;k1=4, name2="hello") # note the ; return Dict("k1" => k1, "name2" => name2) end +# => keyword_args (generic function with 1 method) -keyword_args(name2="ness") # => ["name2"=>"ness","k1"=>4] -keyword_args(k1="mine") # => ["k1"=>"mine","name2"=>"hello"] -keyword_args() # => ["name2"=>"hello","k1"=>4] +keyword_args(name2="ness") # => ["name2"=>"ness", "k1"=>4] +keyword_args(k1="mine") # => ["name2"=>"hello", "k1"=>"mine"] +keyword_args() # => ["name2"=>"hello", "k1"=>4] # You can combine all kinds of arguments in the same function function all_the_args(normal_arg, optional_positional_arg=2; keyword_arg="foo") @@ -463,6 +481,7 @@ function all_the_args(normal_arg, optional_positional_arg=2; keyword_arg="foo") println("optional arg: $optional_positional_arg") println("keyword arg: $keyword_arg") end +# => all_the_args (generic function with 2 methods) all_the_args(1, 3, keyword_arg=4) # prints: @@ -477,6 +496,7 @@ function create_adder(x) end return adder end +# => create_adder (generic function with 1 method) # This is "stabby lambda syntax" for creating anonymous functions (x -> x > 2)(3) # => true @@ -485,6 +505,7 @@ end function create_adder(x) y -> x + y end +# => create_adder (generic function with 1 method) # You can also name the internal function, if you want function create_adder(x) @@ -493,9 +514,11 @@ function create_adder(x) end adder end +# => create_adder (generic function with 1 method) -add_10 = create_adder(10) -add_10(3) # => 13 +add_10 = create_adder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64}) + # (generic function with 1 method) +add_10(3) # => 13 # There are built-in higher order functions @@ -555,16 +578,16 @@ abstract type Cat end # just a name and point in the type hierarchy using InteractiveUtils # defines the subtype and supertype function # For example, Number is an abstract type subtypes(Number) # => 2-element Array{Any,1}: - # Complex{T<:Real} - # Real + # => Complex + # => Real subtypes(Cat) # => 0-element Array{Any,1} # AbstractString, as the name implies, is also an abstract type -subtypes(AbstractString) # 4-element Array{Any,1}: - # String - # SubString - # SubstitutionString - # Test.GenericString +subtypes(AbstractString) # => 4-element Array{Any,1}: + # => String + # => SubString + # => SubstitutionString + # => Test.GenericString # Every type has a super type; use the `supertype` function to get it. typeof(5) # => Int64 @@ -626,7 +649,7 @@ function meow(animal::Tiger) end # Testing the meow function -meow(tigger) # => "rawwr" +meow(tigger) # => "rawwwr" meow(Lion("brown", "ROAAR")) # => "ROAAR" meow(Panther()) # => "grrr" @@ -639,10 +662,11 @@ Panther <: Cat # => true function pet_cat(cat::Cat) println("The cat says $(meow(cat))") end +# => pet_cat (generic function with 1 method) -pet_cat(Lion("42")) # => prints "The cat says 42" +pet_cat(Lion("42")) # => The cat says 42 try - pet_cat(tigger) # => ERROR: no method pet_cat(Tiger,) + pet_cat(tigger) # => ERROR: MethodError: no method matching pet_cat(::Tiger) catch e println(e) end @@ -657,45 +681,54 @@ function fight(t::Tiger, c::Cat) end # => fight (generic function with 1 method) -fight(tigger, Panther()) # => prints The orange tiger wins! -fight(tigger, Lion("ROAR")) # => prints The orange tiger wins! +fight(tigger, Panther()) # => The orange tiger wins! +fight(tigger, Lion("ROAR")) # => The orange tiger wins! # Let's change the behavior when the Cat is specifically a Lion fight(t::Tiger, l::Lion) = println("The $(l.mane_color)-maned lion wins!") # => fight (generic function with 2 methods) -fight(tigger, Panther()) # => prints The orange tiger wins! -fight(tigger, Lion("ROAR")) # => prints The green-maned lion wins! +fight(tigger, Panther()) # => The orange tiger wins! +fight(tigger, Lion("ROAR")) # => The green-maned lion wins! # We don't need a Tiger in order to fight fight(l::Lion, c::Cat) = println("The victorious cat says $(meow(c))") # => fight (generic function with 3 methods) -fight(Lion("balooga!"), Panther()) # => prints The victorious cat says grrr +fight(Lion("balooga!"), Panther()) # => The victorious cat says grrr try - fight(Panther(), Lion("RAWR")) + fight(Panther(), Lion("RAWR")) + # => ERROR: MethodError: no method matching fight(::Panther, ::Lion) + # => Closest candidates are: + # => fight(::Tiger, ::Lion) at ... + # => fight(::Tiger, ::Cat) at ... + # => fight(::Lion, ::Cat) at ... + # => ... catch e println(e) - # => MethodError(fight, (Panther("green"), Lion("green", "RAWR")), - # 0x000000000000557b) end # Also let the cat go first fight(c::Cat, l::Lion) = println("The cat beats the Lion") +# => fight (generic function with 4 methods) # This warning is because it's unclear which fight will be called in: try fight(Lion("RAR"), Lion("brown", "rarrr")) - # => prints The victorious cat says rarrr + # => ERROR: MethodError: fight(::Lion, ::Lion) is ambiguous. Candidates: + # => fight(c::Cat, l::Lion) in Main at ... + # => fight(l::Lion, c::Cat) in Main at ... + # => Possible fix, define + # => fight(::Lion, ::Lion) + # => ... catch e println(e) - # => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")), - # 0x000000000000557c) end # The result may be different in other versions of Julia -fight(l::Lion, l2::Lion) = println("The lions come to a tie") -fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The lions come to a tie +fight(l::Lion, l2::Lion) = println("The lions come to a tie") +# => fight (generic function with 5 methods) +fight(Lion("RAR"), Lion("brown", "rarrr")) # => The lions come to a tie # Under the hood @@ -706,74 +739,112 @@ square_area(l) = l * l # square_area (generic function with 1 method) square_area(5) # => 25 # What happens when we feed square_area an integer? -code_native(square_area, (Int32,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 # Prologue - # push RBP - # mov RBP, RSP - # Source line: 1 - # movsxd RAX, EDI # Fetch l from memory? - # imul RAX, RAX # Square l and store the result in RAX - # pop RBP # Restore old base pointer - # ret # Result will still be in RAX - -code_native(square_area, (Float32,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 - # push RBP - # mov RBP, RSP - # Source line: 1 - # vmulss XMM0, XMM0, XMM0 # Scalar single precision multiply (AVX) - # pop RBP - # ret - -code_native(square_area, (Float64,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 - # push RBP - # mov RBP, RSP - # Source line: 1 - # vmulsd XMM0, XMM0, XMM0 # Scalar double precision multiply (AVX) - # pop RBP - # ret - # +code_native(square_area, (Int32,), syntax = :intel) + # .text + # ; Function square_area { + # ; Location: REPL[116]:1 # Prologue + # push rbp + # mov rbp, rsp + # ; Function *; { + # ; Location: int.jl:54 + # imul ecx, ecx # Square l and store the result in ECX + # ;} + # mov eax, ecx + # pop rbp # Restore old base pointer + # ret # Result will still be in EAX + # nop dword ptr [rax + rax] + # ;} + +code_native(square_area, (Float32,), syntax = :intel) + # .text + # ; Function square_area { + # ; Location: REPL[116]:1 + # push rbp + # mov rbp, rsp + # ; Function *; { + # ; Location: float.jl:398 + # vmulss xmm0, xmm0, xmm0 # Scalar single precision multiply (AVX) + # ;} + # pop rbp + # ret + # nop word ptr [rax + rax] + # ;} + +code_native(square_area, (Float64,), syntax = :intel) + # .text + # ; Function square_area { + # ; Location: REPL[116]:1 + # push rbp + # mov rbp, rsp + # ; Function *; { + # ; Location: float.jl:399 + # vmulsd xmm0, xmm0, xmm0 # Scalar double precision multiply (AVX) + # ;} + # pop rbp + # ret + # nop word ptr [rax + rax] + # ;} + # Note that julia will use floating point instructions if any of the # arguments are floats. # Let's calculate the area of a circle circle_area(r) = pi * r * r # circle_area (generic function with 1 method) circle_area(5) # 78.53981633974483 -code_native(circle_area, (Int32,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 - # push RBP - # mov RBP, RSP - # Source line: 1 - # vcvtsi2sd XMM0, XMM0, EDI # Load integer (r) from memory - # movabs RAX, 4593140240 # Load pi - # vmulsd XMM1, XMM0, QWORD PTR [RAX] # pi * r - # vmulsd XMM0, XMM0, XMM1 # (pi * r) * r - # pop RBP - # ret - # - -code_native(circle_area, (Float64,)) - # .section __TEXT,__text,regular,pure_instructions - # Filename: none - # Source line: 1 - # push RBP - # mov RBP, RSP - # movabs RAX, 4593140496 - # Source line: 1 - # vmulsd XMM1, XMM0, QWORD PTR [RAX] - # vmulsd XMM0, XMM1, XMM0 - # pop RBP - # ret - # +code_native(circle_area, (Int32,), syntax = :intel) + # .text + # ; Function circle_area { + # ; Location: REPL[121]:1 + # push rbp + # mov rbp, rsp + # ; Function *; { + # ; Location: operators.jl:502 + # ; Function *; { + # ; Location: promotion.jl:314 + # ; Function promote; { + # ; Location: promotion.jl:284 + # ; Function _promote; { + # ; Location: promotion.jl:261 + # ; Function convert; { + # ; Location: number.jl:7 + # ; Function Type; { + # ; Location: float.jl:60 + # vcvtsi2sd xmm0, xmm0, ecx # Load integer (r) from memory + # movabs rax, 497710928 # Load pi + # ;}}}}} + # ; Function *; { + # ; Location: float.jl:399 + # vmulsd xmm1, xmm0, qword ptr [rax] # pi * r + # vmulsd xmm0, xmm1, xmm0 # (pi * r) * r + # ;}} + # pop rbp + # ret + # nop dword ptr [rax] + # ;} + +code_native(circle_area, (Float64,), syntax = :intel) + # .text + # ; Function circle_area { + # ; Location: REPL[121]:1 + # push rbp + # mov rbp, rsp + # movabs rax, 497711048 + # ; Function *; { + # ; Location: operators.jl:502 + # ; Function *; { + # ; Location: promotion.jl:314 + # ; Function *; { + # ; Location: float.jl:399 + # vmulsd xmm1, xmm0, qword ptr [rax] + # ;}}} + # ; Function *; { + # ; Location: float.jl:399 + # vmulsd xmm0, xmm1, xmm0 + # ;} + # pop rbp + # ret + # nop dword ptr [rax + rax] + # ;} ``` ## Further Reading -- cgit v1.2.3 From 4fcac31e9cfe169f006244dbdb01d0d16fa696e5 Mon Sep 17 00:00:00 2001 From: 0u0 Date: Fri, 31 Aug 2018 09:45:50 +0800 Subject: ry to use as few words as possible --- julia.html.markdown | 48 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 33 insertions(+), 15 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 416f1a5a..54860fca 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -170,10 +170,12 @@ push!(a, 3) # => [1,2,4,3] append!(a, b) # => [1,2,4,3,4,5,6] # Remove from the end with pop -pop!(b) # => 6 and b is now [4,5] +pop!(b) # => 6 +b # => [4,5] # Let's put it back -push!(b, 6) # b is now [4,5,6] again. +push!(b, 6) # => [4,5,6] +b # => [4,5,6] a[1] # => 1 # remember that Julia indexes from 1, not 0! @@ -182,14 +184,18 @@ a[1] # => 1 # remember that Julia indexes from 1, not 0! a[end] # => 6 # we also have popfirst! and pushfirst! -popfirst!(a) # => 1 and a is now [2,4,3,4,5,6] +popfirst!(a) # => 1 +a # => [2,4,3,4,5,6] pushfirst!(a, 7) # => [7,2,4,3,4,5,6] +a # => [7,2,4,3,4,5,6] # Function names that end in exclamations points indicate that they modify # their argument. -sort(arr) # => [4,5,6]; arr is still [5,4,6] -sort!(arr) # => [4,5,6]; arr is now [4,5,6] arr = [5,4,6] # => 3-element Array{Int64,1}: [5,4,6] +sort(arr) # => [4,5,6] +arr # => [5,4,6] +sort!(arr) # => [4,5,6] +arr # => [4,5,6] # Looking out of bounds is a BoundsError try @@ -227,11 +233,13 @@ a[2:end] # => [2, 3, 4, 5] # Remove elements from an array by index with splice! arr = [3,4,5] -splice!(arr, 2) # => 4 ; arr is now [3,5] +splice!(arr, 2) # => 4 +arr # => [3,5] # Concatenate lists with append! b = [1,2,3] -append!(a, b) # Now a is [1, 2, 3, 4, 5, 1, 2, 3] +append!(a, b) # => [1, 2, 3, 4, 5, 1, 2, 3] +a # => [1, 2, 3, 4, 5, 1, 2, 3] # Check for existence in a list with in in(1, a) # => true @@ -240,8 +248,9 @@ in(1, a) # => true length(a) # => 8 # Tuples are immutable. -tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple. -tup[1] # => 1 +tup = (1, 2, 3) # => (1,2,3) +typeof(tup) # => Tuple{Int64,Int64,Int64} +tup[1] # => 1 try tup[1] = 3 # => ERROR: MethodError: no method matching @@ -251,23 +260,30 @@ catch e end # Many array functions also work on tuples -length(tup) # => 3 -tup[1:2] # => (1,2) +length(tup) # => 3 +tup[1:2] # => (1,2) in(2, tup) # => true # You can unpack tuples into variables -a, b, c = (1, 2, 3) # => (1,2,3) # a is now 1, b is now 2 and c is now 3 +a, b, c = (1, 2, 3) # => (1,2,3) +a # => 1 +b # => 2 +c # => 3 # Tuples are created even if you leave out the parentheses d, e, f = 4, 5, 6 # => (4,5,6) +d # => 4 +e # => 5 +f # => 6 # A 1-element tuple is distinct from the value it contains (1,) == 1 # => false (1) == 1 # => true # Look how easy it is to swap two values -e, d = d, e # => (5,4) # d is now 5 and e is now 4 - +e, d = d, e # => (5,4) +d # => 5 +e # => 4 # Dictionaries store mappings empty_dict = Dict() # => Dict{Any,Any} with 0 entries @@ -419,7 +435,9 @@ function add(x, y) x + y end -add(5, 6) # => 11 after printing out "x is 5 and y is 6" +add(5, 6) +# => x is 5 and y is 6 +# => 11 # Compact assignment of functions f_add(x, y) = x + y # => f_add (generic function with 1 method) -- cgit v1.2.3 From 749e81ace2cf75710926cc0e9e35a8a675545648 Mon Sep 17 00:00:00 2001 From: 0u0 Date: Fri, 31 Aug 2018 09:46:52 +0800 Subject: Uniform output format --- julia.html.markdown | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 54860fca..fa614992 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -369,19 +369,17 @@ for animal = ["dog", "cat", "mouse"] println("$animal is a mammal") # You can use $ to interpolate variables or expression into strings end -# prints: -# dog is a mammal -# cat is a mammal -# mouse is a mammal +# => dog is a mammal +# => cat is a mammal +# => mouse is a mammal # You can use 'in' instead of '='. for animal in ["dog", "cat", "mouse"] println("$animal is a mammal") end -# prints: -# dog is a mammal -# cat is a mammal -# mouse is a mammal +# => dog is a mammal +# => cat is a mammal +# => mouse is a mammal for pair in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal") from, to = pair @@ -405,11 +403,10 @@ let x = 0 x += 1 # Shorthand for x = x + 1 end end -# prints: -# 0 -# 1 -# 2 -# 3 +# => 0 +# => 1 +# => 2 +# => 3 # Handle exceptions with a try/catch block try @@ -502,10 +499,9 @@ end # => all_the_args (generic function with 2 methods) all_the_args(1, 3, keyword_arg=4) -# prints: -# normal arg: 1 -# optional arg: 3 -# keyword arg: 4 +# => normal arg: 1 +# => optional arg: 3 +# => keyword arg: 4 # Julia has first class functions function create_adder(x) -- cgit v1.2.3 From e96bfe490e2df68075e277cb18bdf58f90af2c0a Mon Sep 17 00:00:00 2001 From: 0u0 Date: Fri, 31 Aug 2018 09:47:30 +0800 Subject: Adjust for alignment --- julia.html.markdown | 51 +++++++++++++++++++++++++-------------------------- 1 file changed, 25 insertions(+), 26 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index fa614992..eadf6415 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -154,6 +154,7 @@ a = Int64[] # => 0-element Array{Int64,1} # 1-dimensional array literals can be written with comma-separated values. b = [4, 5, 6] # => 3-element Array{Int64,1}: [4, 5, 6] b = [4; 5; 6] # => 3-element Array{Int64,1}: [4, 5, 6] +b[1] # => 4 b[end] # => 6 # 2-dimensional arrays use space-separated values and semicolon-separated rows. @@ -277,7 +278,7 @@ e # => 5 f # => 6 # A 1-element tuple is distinct from the value it contains -(1,) == 1 # => false +(1,) == 1 # => false (1) == 1 # => true # Look how easy it is to swap two values @@ -335,15 +336,14 @@ filled_set = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1]) push!(filled_set, 5) # => Set([4, 2, 3, 5, 1]) # Check if the values are in the set -in(2, filled_set) # => true +in(2, filled_set) # => true in(10, filled_set) # => false # There are functions for set intersection, union, and difference. -other_set = Set([3, 4, 5, 6]) # => Set([4, 3, 5, 6]) -intersect(filled_set, other_set) # => Set([4, 3, 5]) -union(filled_set, other_set) # => Set([4, 2, 3, 5, 6, 1]) -setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set([4, 1]) - +other_set = Set([3, 4, 5, 6]) # => Set([4, 3, 5, 6]) +intersect(filled_set, other_set) # => Set([4, 3, 5]) +union(filled_set, other_set) # => Set([4, 2, 3, 5, 6, 1]) +setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set([4, 1]) #################################################### ## 3. Control Flow @@ -416,15 +416,14 @@ catch e end # => caught it ErrorException("help") - #################################################### ## 4. Functions #################################################### # The keyword 'function' creates new functions -#function name(arglist) -# body... -#end +# function name(arglist) +# body... +# end function add(x, y) println("x is $x and y is $y") @@ -540,8 +539,8 @@ map(add_10, [1,2,3]) # => [11, 12, 13] filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # We can use list comprehensions -[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13] -[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] +[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13] +[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] [x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7] #################################################### @@ -554,7 +553,7 @@ filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] typeof(5) # => Int64 # Types are first-class values -typeof(Int64) # => DataType +typeof(Int64) # => DataType typeof(DataType) # => DataType # DataType is the type that represents types, including itself. @@ -604,17 +603,17 @@ subtypes(AbstractString) # => 4-element Array{Any,1}: # => Test.GenericString # Every type has a super type; use the `supertype` function to get it. -typeof(5) # => Int64 -supertype(Int64) # => Signed -supertype(Signed) # => Integer +typeof(5) # => Int64 +supertype(Int64) # => Signed +supertype(Signed) # => Integer supertype(Integer) # => Real -supertype(Real) # => Number -supertype(Number) # => Any +supertype(Real) # => Number +supertype(Number) # => Any supertype(supertype(Signed)) # => Real -supertype(Any) # => Any +supertype(Any) # => Any # All of these type, except for Int64, are abstract. -typeof("fire") # => String -supertype(String) # => AbstractString +typeof("fire") # => String +supertype(String) # => AbstractString # Likewise here with String supertype(SubString) # => AbstractString @@ -665,12 +664,12 @@ end # Testing the meow function meow(tigger) # => "rawwwr" meow(Lion("brown", "ROAAR")) # => "ROAAR" -meow(Panther()) # => "grrr" +meow(Panther()) # => "grrr" # Review the local type hierarchy -Tiger <: Cat # => false -Lion <: Cat # => true -Panther <: Cat # => true +Tiger <: Cat # => false +Lion <: Cat # => true +Panther <: Cat # => true # Defining a function that takes Cats function pet_cat(cat::Cat) -- cgit v1.2.3 From b0bbe39b46a1825563c903c0e9c25eed3c63293b Mon Sep 17 00:00:00 2001 From: 0u0 Date: Fri, 31 Aug 2018 09:50:30 +0800 Subject: remove useless Blank Lines --- julia.html.markdown | 2 -- 1 file changed, 2 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index eadf6415..3ef3148a 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -14,7 +14,6 @@ and low-level control, Julia is as easy to learn and use as Python. This is based on Julia 1.0.0 ```julia - # Single line comments start with a hash (pound) symbol. #= Multiline comments can be written by putting '#=' before the text and '=#' @@ -362,7 +361,6 @@ else # The else clause is optional too. end # => prints "some var is smaller than 10" - # For loops iterate over iterables. # Iterable types include Range, Array, Set, Dict, and AbstractString. for animal = ["dog", "cat", "mouse"] -- cgit v1.2.3 From 2a7bf762c65a50a609cc65c275267203309f97be Mon Sep 17 00:00:00 2001 From: 0u0 Date: Fri, 31 Aug 2018 11:24:57 +0800 Subject: Remove useless lib In fact, if you donot import InteractiveUtils, you still can use the subtype and supertype function --- julia.html.markdown | 1 - 1 file changed, 1 deletion(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 3ef3148a..15c09da4 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -586,7 +586,6 @@ sherekhan = typeof(tigger)(5.6, "fire") # => Tiger(5.6,"fire") abstract type Cat end # just a name and point in the type hierarchy # Abstract types cannot be instantiated, but can have subtypes. -using InteractiveUtils # defines the subtype and supertype function # For example, Number is an abstract type subtypes(Number) # => 2-element Array{Any,1}: # => Complex -- cgit v1.2.3 From f894add86a84b378529b53813fb28fb31efe9628 Mon Sep 17 00:00:00 2001 From: Keith Miyake Date: Thu, 4 Oct 2018 12:34:19 -0700 Subject: [julia/en] fix for #1483 --- julia.html.markdown | 154 ++++++++++++++++++++++++++-------------------------- 1 file changed, 77 insertions(+), 77 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 15c09da4..839e414d 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -114,12 +114,12 @@ println("I'm Julia. Nice to meet you!") # => I'm Julia. Nice to meet you! #################################################### # You don't declare variables before assigning to them. -some_var = 5 # => 5 -some_var # => 5 +someVar = 5 # => 5 +someVar # => 5 # Accessing a previously unassigned variable is an error try - some_other_var # => ERROR: UndefVarError: some_other_var not defined + someOtherVar # => ERROR: UndefVarError: someOtherVar not defined catch e println(e) end @@ -286,62 +286,62 @@ d # => 5 e # => 4 # Dictionaries store mappings -empty_dict = Dict() # => Dict{Any,Any} with 0 entries +emptyDict = Dict() # => Dict{Any,Any} with 0 entries # You can create a dictionary using a literal -filled_dict = Dict("one" => 1, "two" => 2, "three" => 3) +filledDict = Dict("one" => 1, "two" => 2, "three" => 3) # => Dict{String,Int64} with 3 entries: # => "two" => 2, "one" => 1, "three" => 3 # Look up values with [] -filled_dict["one"] # => 1 +filledDict["one"] # => 1 # Get all keys -keys(filled_dict) +keys(filledDict) # => Base.KeySet for a Dict{String,Int64} with 3 entries. Keys: # => "two", "one", "three" # Note - dictionary keys are not sorted or in the order you inserted them. # Get all values -values(filled_dict) +values(filledDict) # => Base.ValueIterator for a Dict{String,Int64} with 3 entries. Values: # => 2, 1, 3 # Note - Same as above regarding key ordering. # Check for existence of keys in a dictionary with in, haskey -in(("one" => 1), filled_dict) # => true -in(("two" => 3), filled_dict) # => false -haskey(filled_dict, "one") # => true -haskey(filled_dict, 1) # => false +in(("one" => 1), filledDict) # => true +in(("two" => 3), filledDict) # => false +haskey(filledDict, "one") # => true +haskey(filledDict, 1) # => false # Trying to look up a non-existent key will raise an error try - filled_dict["four"] # => ERROR: KeyError: key "four" not found + filledDict["four"] # => ERROR: KeyError: key "four" not found catch e println(e) end # Use the get method to avoid that error by providing a default value -# get(dictionary, key, default_value) -get(filled_dict, "one", 4) # => 1 -get(filled_dict, "four", 4) # => 4 +# get(dictionary, key, defaultValue) +get(filledDict, "one", 4) # => 1 +get(filledDict, "four", 4) # => 4 # Use Sets to represent collections of unordered, unique values -empty_set = Set() # => Set(Any[]) +emptySet = Set() # => Set(Any[]) # Initialize a set with values -filled_set = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1]) +filledSet = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1]) # Add more values to a set -push!(filled_set, 5) # => Set([4, 2, 3, 5, 1]) +push!(filledSet, 5) # => Set([4, 2, 3, 5, 1]) # Check if the values are in the set -in(2, filled_set) # => true -in(10, filled_set) # => false +in(2, filledSet) # => true +in(10, filledSet) # => false # There are functions for set intersection, union, and difference. -other_set = Set([3, 4, 5, 6]) # => Set([4, 3, 5, 6]) -intersect(filled_set, other_set) # => Set([4, 3, 5]) -union(filled_set, other_set) # => Set([4, 2, 3, 5, 6, 1]) +otherSet = Set([3, 4, 5, 6]) # => Set([4, 3, 5, 6]) +intersect(filledSet, otherSet) # => Set([4, 3, 5]) +union(filledSet, otherSet) # => Set([4, 2, 3, 5, 6, 1]) setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set([4, 1]) #################################################### @@ -349,15 +349,15 @@ setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set([4, 1]) #################################################### # Let's make a variable -some_var = 5 +someVar = 5 # Here is an if statement. Indentation is not meaningful in Julia. -if some_var > 10 - println("some_var is totally bigger than 10.") -elseif some_var < 10 # This elseif clause is optional. - println("some_var is smaller than 10.") +if someVar > 10 + println("someVar is totally bigger than 10.") +elseif someVar < 10 # This elseif clause is optional. + println("someVar is smaller than 10.") else # The else clause is optional too. - println("some_var is indeed 10.") + println("someVar is indeed 10.") end # => prints "some var is smaller than 10" @@ -434,8 +434,8 @@ add(5, 6) # => 11 # Compact assignment of functions -f_add(x, y) = x + y # => f_add (generic function with 1 method) -f_add(3, 4) # => 7 +fAdd(x, y) = x + y # => fAdd (generic function with 1 method) +fAdd(3, 4) # => 7 # Function can also return multiple values as tuple fn(x, y) = x + y, x - y # => fn (generic function with 1 method) @@ -478,67 +478,67 @@ catch e end # You can define functions that take keyword arguments -function keyword_args(;k1=4, name2="hello") # note the ; +function keywordArgs(;k1=4, name2="hello") # note the ; return Dict("k1" => k1, "name2" => name2) end -# => keyword_args (generic function with 1 method) +# => keywordArgs (generic function with 1 method) -keyword_args(name2="ness") # => ["name2"=>"ness", "k1"=>4] -keyword_args(k1="mine") # => ["name2"=>"hello", "k1"=>"mine"] -keyword_args() # => ["name2"=>"hello", "k1"=>4] +keywordArgs(name2="ness") # => ["name2"=>"ness", "k1"=>4] +keywordArgs(k1="mine") # => ["name2"=>"hello", "k1"=>"mine"] +keywordArgs() # => ["name2"=>"hello", "k1"=>4] # You can combine all kinds of arguments in the same function -function all_the_args(normal_arg, optional_positional_arg=2; keyword_arg="foo") - println("normal arg: $normal_arg") - println("optional arg: $optional_positional_arg") - println("keyword arg: $keyword_arg") +function allTheArgs(normalArg, optionalPositionalArg=2; keywordArg="foo") + println("normal arg: $normalArg") + println("optional arg: $optionalPositionalArg") + println("keyword arg: $keywordArg") end -# => all_the_args (generic function with 2 methods) +# => allTheArgs (generic function with 2 methods) -all_the_args(1, 3, keyword_arg=4) +allAheArgs(1, 3, keywordArg=4) # => normal arg: 1 # => optional arg: 3 # => keyword arg: 4 # Julia has first class functions -function create_adder(x) +function createAdder(x) adder = function (y) return x + y end return adder end -# => create_adder (generic function with 1 method) +# => createAdder (generic function with 1 method) # This is "stabby lambda syntax" for creating anonymous functions (x -> x > 2)(3) # => true -# This function is identical to create_adder implementation above. -function create_adder(x) +# This function is identical to createAdder implementation above. +function createAdder(x) y -> x + y end -# => create_adder (generic function with 1 method) +# => createAdder (generic function with 1 method) # You can also name the internal function, if you want -function create_adder(x) +function createAdder(x) function adder(y) x + y end adder end -# => create_adder (generic function with 1 method) +# => createAdder (generic function with 1 method) -add_10 = create_adder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64}) +add10 = createAdder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64}) # (generic function with 1 method) -add_10(3) # => 13 +add10(3) # => 13 # There are built-in higher order functions -map(add_10, [1,2,3]) # => [11, 12, 13] +map(add10, [1,2,3]) # => [11, 12, 13] filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # We can use list comprehensions -[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13] -[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] +[add10(i) for i = [1, 2, 3]] # => [11, 12, 13] +[add10(i) for i in [1, 2, 3]] # => [11, 12, 13] [x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7] #################################################### @@ -616,7 +616,7 @@ supertype(SubString) # => AbstractString # <: is the subtyping operator struct Lion <: Cat # Lion is a subtype of Cat - mane_color + maneColor roar::AbstractString end @@ -627,7 +627,7 @@ Lion(roar::AbstractString) = Lion("green", roar) # This is an outer constructor because it's outside the type definition struct Panther <: Cat # Panther is also a subtype of Cat - eye_color + eyeColor Panther() = new("green") # Panthers will only have this constructor, and no default constructor. end @@ -669,14 +669,14 @@ Lion <: Cat # => true Panther <: Cat # => true # Defining a function that takes Cats -function pet_cat(cat::Cat) +function petCat(cat::Cat) println("The cat says $(meow(cat))") end -# => pet_cat (generic function with 1 method) +# => petCat (generic function with 1 method) -pet_cat(Lion("42")) # => The cat says 42 +petCat(Lion("42")) # => The cat says 42 try - pet_cat(tigger) # => ERROR: MethodError: no method matching pet_cat(::Tiger) + petCat(tigger) # => ERROR: MethodError: no method matching petCat(::Tiger) catch e println(e) end @@ -695,7 +695,7 @@ fight(tigger, Panther()) # => The orange tiger wins! fight(tigger, Lion("ROAR")) # => The orange tiger wins! # Let's change the behavior when the Cat is specifically a Lion -fight(t::Tiger, l::Lion) = println("The $(l.mane_color)-maned lion wins!") +fight(t::Tiger, l::Lion) = println("The $(l.maneColor)-maned lion wins!") # => fight (generic function with 2 methods) fight(tigger, Panther()) # => The orange tiger wins! @@ -744,14 +744,14 @@ fight(Lion("RAR"), Lion("brown", "rarrr")) # => The lions come to a tie # Under the hood # You can take a look at the llvm and the assembly code generated. -square_area(l) = l * l # square_area (generic function with 1 method) +squareArea(l) = l * l # squareArea (generic function with 1 method) -square_area(5) # => 25 +squareArea(5) # => 25 -# What happens when we feed square_area an integer? -code_native(square_area, (Int32,), syntax = :intel) +# What happens when we feed squareArea an integer? +codeNative(squareArea, (Int32,), syntax = :intel) # .text - # ; Function square_area { + # ; Function squareArea { # ; Location: REPL[116]:1 # Prologue # push rbp # mov rbp, rsp @@ -765,9 +765,9 @@ code_native(square_area, (Int32,), syntax = :intel) # nop dword ptr [rax + rax] # ;} -code_native(square_area, (Float32,), syntax = :intel) +codeNative(squareArea, (Float32,), syntax = :intel) # .text - # ; Function square_area { + # ; Function squareArea { # ; Location: REPL[116]:1 # push rbp # mov rbp, rsp @@ -780,9 +780,9 @@ code_native(square_area, (Float32,), syntax = :intel) # nop word ptr [rax + rax] # ;} -code_native(square_area, (Float64,), syntax = :intel) +codeNative(squareArea, (Float64,), syntax = :intel) # .text - # ; Function square_area { + # ; Function squareArea { # ; Location: REPL[116]:1 # push rbp # mov rbp, rsp @@ -798,12 +798,12 @@ code_native(square_area, (Float64,), syntax = :intel) # Note that julia will use floating point instructions if any of the # arguments are floats. # Let's calculate the area of a circle -circle_area(r) = pi * r * r # circle_area (generic function with 1 method) -circle_area(5) # 78.53981633974483 +circleArea(r) = pi * r * r # circleArea (generic function with 1 method) +circleArea(5) # 78.53981633974483 -code_native(circle_area, (Int32,), syntax = :intel) +codeNative(circleArea, (Int32,), syntax = :intel) # .text - # ; Function circle_area { + # ; Function circleArea { # ; Location: REPL[121]:1 # push rbp # mov rbp, rsp @@ -832,9 +832,9 @@ code_native(circle_area, (Int32,), syntax = :intel) # nop dword ptr [rax] # ;} -code_native(circle_area, (Float64,), syntax = :intel) +codeNative(circleArea, (Float64,), syntax = :intel) # .text - # ; Function circle_area { + # ; Function circleArea { # ; Location: REPL[121]:1 # push rbp # mov rbp, rsp -- cgit v1.2.3 From 3499b8358988307eb97481427e345c8fa94e57fc Mon Sep 17 00:00:00 2001 From: Keith Miyake Date: Thu, 4 Oct 2018 15:51:04 -0700 Subject: [julia/en] camelCase functions => snake_case --- julia.html.markdown | 74 ++++++++++++++++++++++++++--------------------------- 1 file changed, 37 insertions(+), 37 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 839e414d..7914f154 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -434,8 +434,8 @@ add(5, 6) # => 11 # Compact assignment of functions -fAdd(x, y) = x + y # => fAdd (generic function with 1 method) -fAdd(3, 4) # => 7 +f_add(x, y) = x + y # => f_add (generic function with 1 method) +f_add(3, 4) # => 7 # Function can also return multiple values as tuple fn(x, y) = x + y, x - y # => fn (generic function with 1 method) @@ -478,56 +478,56 @@ catch e end # You can define functions that take keyword arguments -function keywordArgs(;k1=4, name2="hello") # note the ; +function keyword_args(;k1=4, name2="hello") # note the ; return Dict("k1" => k1, "name2" => name2) end -# => keywordArgs (generic function with 1 method) +# => keyword_args (generic function with 1 method) -keywordArgs(name2="ness") # => ["name2"=>"ness", "k1"=>4] -keywordArgs(k1="mine") # => ["name2"=>"hello", "k1"=>"mine"] -keywordArgs() # => ["name2"=>"hello", "k1"=>4] +keyword_args(name2="ness") # => ["name2"=>"ness", "k1"=>4] +keyword_args(k1="mine") # => ["name2"=>"hello", "k1"=>"mine"] +keyword_args() # => ["name2"=>"hello", "k1"=>4] # You can combine all kinds of arguments in the same function -function allTheArgs(normalArg, optionalPositionalArg=2; keywordArg="foo") +function all_the_args(normalArg, optionalPositionalArg=2; keywordArg="foo") println("normal arg: $normalArg") println("optional arg: $optionalPositionalArg") println("keyword arg: $keywordArg") end -# => allTheArgs (generic function with 2 methods) +# => all_the_args (generic function with 2 methods) -allAheArgs(1, 3, keywordArg=4) +all_the_args(1, 3, keywordArg=4) # => normal arg: 1 # => optional arg: 3 # => keyword arg: 4 # Julia has first class functions -function createAdder(x) +function create_adder(x) adder = function (y) return x + y end return adder end -# => createAdder (generic function with 1 method) +# => create_adder (generic function with 1 method) # This is "stabby lambda syntax" for creating anonymous functions (x -> x > 2)(3) # => true -# This function is identical to createAdder implementation above. -function createAdder(x) +# This function is identical to create_adder implementation above. +function create_adder(x) y -> x + y end -# => createAdder (generic function with 1 method) +# => create_adder (generic function with 1 method) # You can also name the internal function, if you want -function createAdder(x) +function create_adder(x) function adder(y) x + y end adder end -# => createAdder (generic function with 1 method) +# => create_adder (generic function with 1 method) -add10 = createAdder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64}) +add10 = create_adder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64}) # (generic function with 1 method) add10(3) # => 13 @@ -669,14 +669,14 @@ Lion <: Cat # => true Panther <: Cat # => true # Defining a function that takes Cats -function petCat(cat::Cat) +function pet_cat(cat::Cat) println("The cat says $(meow(cat))") end -# => petCat (generic function with 1 method) +# => pet_cat (generic function with 1 method) -petCat(Lion("42")) # => The cat says 42 +pet_cat(Lion("42")) # => The cat says 42 try - petCat(tigger) # => ERROR: MethodError: no method matching petCat(::Tiger) + pet_cat(tigger) # => ERROR: MethodError: no method matching pet_cat(::Tiger) catch e println(e) end @@ -744,14 +744,14 @@ fight(Lion("RAR"), Lion("brown", "rarrr")) # => The lions come to a tie # Under the hood # You can take a look at the llvm and the assembly code generated. -squareArea(l) = l * l # squareArea (generic function with 1 method) +square_area(l) = l * l # square_area (generic function with 1 method) -squareArea(5) # => 25 +square_area(5) # => 25 -# What happens when we feed squareArea an integer? -codeNative(squareArea, (Int32,), syntax = :intel) +# What happens when we feed square_area an integer? +codeNative(square_area, (Int32,), syntax = :intel) # .text - # ; Function squareArea { + # ; Function square_area { # ; Location: REPL[116]:1 # Prologue # push rbp # mov rbp, rsp @@ -765,9 +765,9 @@ codeNative(squareArea, (Int32,), syntax = :intel) # nop dword ptr [rax + rax] # ;} -codeNative(squareArea, (Float32,), syntax = :intel) +codeNative(square_area, (Float32,), syntax = :intel) # .text - # ; Function squareArea { + # ; Function square_area { # ; Location: REPL[116]:1 # push rbp # mov rbp, rsp @@ -780,9 +780,9 @@ codeNative(squareArea, (Float32,), syntax = :intel) # nop word ptr [rax + rax] # ;} -codeNative(squareArea, (Float64,), syntax = :intel) +codeNative(square_area, (Float64,), syntax = :intel) # .text - # ; Function squareArea { + # ; Function square_area { # ; Location: REPL[116]:1 # push rbp # mov rbp, rsp @@ -798,12 +798,12 @@ codeNative(squareArea, (Float64,), syntax = :intel) # Note that julia will use floating point instructions if any of the # arguments are floats. # Let's calculate the area of a circle -circleArea(r) = pi * r * r # circleArea (generic function with 1 method) -circleArea(5) # 78.53981633974483 +circle_area(r) = pi * r * r # circle_area (generic function with 1 method) +circle_area(5) # 78.53981633974483 -codeNative(circleArea, (Int32,), syntax = :intel) +codeNative(circle_area, (Int32,), syntax = :intel) # .text - # ; Function circleArea { + # ; Function circle_area { # ; Location: REPL[121]:1 # push rbp # mov rbp, rsp @@ -832,9 +832,9 @@ codeNative(circleArea, (Int32,), syntax = :intel) # nop dword ptr [rax] # ;} -codeNative(circleArea, (Float64,), syntax = :intel) +codeNative(circle_area, (Float64,), syntax = :intel) # .text - # ; Function circleArea { + # ; Function circle_area { # ; Location: REPL[121]:1 # push rbp # mov rbp, rsp -- cgit v1.2.3 From 7bd6f99b6b85ee9977be9f1212a8799876e5743c Mon Sep 17 00:00:00 2001 From: Keith Miyake Date: Thu, 4 Oct 2018 15:55:35 -0700 Subject: [julia/en] snake_case one more function name that slipped past --- julia.html.markdown | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 7914f154..0bb629d3 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -527,18 +527,18 @@ function create_adder(x) end # => create_adder (generic function with 1 method) -add10 = create_adder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64}) +add_10 = create_adder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64}) # (generic function with 1 method) -add10(3) # => 13 +add_10(3) # => 13 # There are built-in higher order functions -map(add10, [1,2,3]) # => [11, 12, 13] +map(add_10, [1,2,3]) # => [11, 12, 13] filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # We can use list comprehensions -[add10(i) for i = [1, 2, 3]] # => [11, 12, 13] -[add10(i) for i in [1, 2, 3]] # => [11, 12, 13] +[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13] +[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] [x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7] #################################################### -- cgit v1.2.3 From 9a8e722661c1afd0702e2174df54f8682b1fea44 Mon Sep 17 00:00:00 2001 From: Keith Miyake Date: Sat, 6 Oct 2018 23:43:50 -0700 Subject: [julia/en] divayprakash has an amazing eagle eye for function naming! --- julia.html.markdown | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 0bb629d3..2fe05c49 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -749,7 +749,7 @@ square_area(l) = l * l # square_area (generic function with 1 method) square_area(5) # => 25 # What happens when we feed square_area an integer? -codeNative(square_area, (Int32,), syntax = :intel) +code_native(square_area, (Int32,), syntax = :intel) # .text # ; Function square_area { # ; Location: REPL[116]:1 # Prologue @@ -765,7 +765,7 @@ codeNative(square_area, (Int32,), syntax = :intel) # nop dword ptr [rax + rax] # ;} -codeNative(square_area, (Float32,), syntax = :intel) +code_native(square_area, (Float32,), syntax = :intel) # .text # ; Function square_area { # ; Location: REPL[116]:1 @@ -780,7 +780,7 @@ codeNative(square_area, (Float32,), syntax = :intel) # nop word ptr [rax + rax] # ;} -codeNative(square_area, (Float64,), syntax = :intel) +code_native(square_area, (Float64,), syntax = :intel) # .text # ; Function square_area { # ; Location: REPL[116]:1 @@ -801,7 +801,7 @@ codeNative(square_area, (Float64,), syntax = :intel) circle_area(r) = pi * r * r # circle_area (generic function with 1 method) circle_area(5) # 78.53981633974483 -codeNative(circle_area, (Int32,), syntax = :intel) +code_native(circle_area, (Int32,), syntax = :intel) # .text # ; Function circle_area { # ; Location: REPL[121]:1 @@ -832,7 +832,7 @@ codeNative(circle_area, (Int32,), syntax = :intel) # nop dword ptr [rax] # ;} -codeNative(circle_area, (Float64,), syntax = :intel) +code_native(circle_area, (Float64,), syntax = :intel) # .text # ; Function circle_area { # ; Location: REPL[121]:1 -- cgit v1.2.3 From 5286a86efa7113e5386b33d576c27eb1e79d3ba6 Mon Sep 17 00:00:00 2001 From: Divay Prakash Date: Sun, 18 Nov 2018 00:49:39 +0530 Subject: Add push! explanation, closes #2047 --- julia.html.markdown | 2 ++ 1 file changed, 2 insertions(+) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 2fe05c49..69b6aa0c 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -163,6 +163,8 @@ matrix = [1 2; 3 4] # => 2×2 Array{Int64,2}: [1 2; 3 4] b = Int8[4, 5, 6] # => 3-element Array{Int8,1}: [4, 5, 6] # Add stuff to the end of a list with push! and append! +# By convention, the exclamation mark '!'' is appended to names of functions +# that modify their arguments push!(a, 1) # => [1] push!(a, 2) # => [1,2] push!(a, 4) # => [1,2,4] -- cgit v1.2.3 From acc52c21e134e4c47f589a2b83fe0152b0a30e67 Mon Sep 17 00:00:00 2001 From: Lyndon White Date: Sun, 20 Jan 2019 23:21:48 +0000 Subject: tweak order of string functions / print functions --- julia.html.markdown | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index 69b6aa0c..eabb988e 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -93,21 +93,22 @@ ascii("This is a string")[1] # Julia indexes from 1 # Otherwise, iterating over strings is recommended (map, for loops, etc). +# String can be compared lexicographically +"good" > "bye" # => true +"good" == "good" # => true +"1 + 2 = 3" == "1 + 2 = $(1 + 2)" # => true + # $ can be used for string interpolation: "2 + 2 = $(2 + 2)" # => "2 + 2 = 4" # You can put any Julia expression inside the parentheses. +# Printing is easy +println("I'm Julia. Nice to meet you!") # => I'm Julia. Nice to meet you! + # Another way to format strings is the printf macro from the stdlib Printf. using Printf @printf "%d is less than %f\n" 4.5 5.3 # => 5 is less than 5.300000 -# Printing is easy -println("I'm Julia. Nice to meet you!") # => I'm Julia. Nice to meet you! - -# String can be compared lexicographically -"good" > "bye" # => true -"good" == "good" # => true -"1 + 2 = 3" == "1 + 2 = $(1 + 2)" # => true #################################################### ## 2. Variables and Collections -- cgit v1.2.3 From 18c010ecd9b654be5bf6d4dfcd68aeb41edfc3a1 Mon Sep 17 00:00:00 2001 From: Thibaut Lienart Date: Mon, 18 Feb 2019 12:25:23 +1100 Subject: Add note about integer overflow Something that may trip users coming from a Python background as per https://discourse.julialang.org/t/julia-messes-up-integer-exponents/20773 --- julia.html.markdown | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'julia.html.markdown') diff --git a/julia.html.markdown b/julia.html.markdown index eabb988e..5e9ef1b8 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -46,6 +46,13 @@ div(5, 2) # => 2 # for a truncated result, use div # Enforce precedence with parentheses (1 + 3) * 2 # => 8 +# Julia (unlike Python for instance) has integer under/overflow +10^19 # => -8446744073709551616 +# use bigint or floating point to avoid this +big(10)^19 # => 10000000000000000000 +1e19 # => 1.0e19 +10.0^19 # => 1.0e19 + # Bitwise Operators ~2 # => -3 # bitwise not 3 & 5 # => 1 # bitwise and -- cgit v1.2.3