diff options
Diffstat (limited to 'julia.html.markdown')
| -rw-r--r-- | julia.html.markdown | 59 |
1 files changed, 36 insertions, 23 deletions
diff --git a/julia.html.markdown b/julia.html.markdown index c5089dc3..23d834f4 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -2,13 +2,14 @@ language: Julia contributors: - ["Leah Hanson", "http://leahhanson.us"] + - ["Pranit Bauva", "http://github.com/pranitbauva1997"] 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 0.3. +This is based on Julia 0.4. ```ruby @@ -22,7 +23,7 @@ This is based on Julia 0.3. ## 1. Primitive Datatypes and Operators #################################################### -# Everything in Julia is a expression. +# Everything in Julia is an expression. # There are several basic types of numbers. 3 # => 3 (Int64) @@ -102,6 +103,11 @@ false # Printing is easy 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 + #################################################### ## 2. Variables and Collections #################################################### @@ -117,11 +123,11 @@ catch e println(e) end -# Variable names start with a letter. +# Variable names start with a letter or underscore. # After that, you can use letters, digits, underscores, and exclamation points. SomeOtherVar123! = 6 # => 6 -# You can also use unicode characters +# You can also use certain unicode characters ☃ = 8 # => 8 # These are especially handy for mathematical notation 2 * π # => 6.283185307179586 @@ -145,12 +151,16 @@ 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 -# 2-dimentional arrays use space-separated values and semicolon-separated rows. +# 2-dimensional arrays use space-separated values and semicolon-separated rows. 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] + # Add stuff to the end of a list with push! and append! push!(a,1) # => [1] push!(a,2) # => [1,2] @@ -262,8 +272,8 @@ 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 +in(("one" => 1), filled_dict) # => true +in(("two" => 3), filled_dict) # => false haskey(filled_dict, "one") # => true haskey(filled_dict, 1) # => false @@ -282,7 +292,7 @@ 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{Int64}(1,2,3,4) # Add more values to a set push!(filled_set,5) # => Set{Int64}(5,4,2,3,1) @@ -292,7 +302,7 @@ 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) +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) @@ -390,6 +400,14 @@ 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(3, 4) # => 7 + +# Function can also return multiple values as tuple +f(x, y) = x + y, x - y +f(3, 4) # => (7, -1) + # You can define functions that take a variable number of # positional arguments function varargs(args...) @@ -402,14 +420,12 @@ 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 fuction call, +# It can also be used in a function call, # where it will splat an Array or Tuple's contents into the argument list. -Set([1,2,3]) # => Set{Array{Int64,1}}([1,2,3]) # produces a Set of Arrays -Set([1,2,3]...) # => Set{Int64}(1,2,3) # this is equivalent to Set(1,2,3) +add([5,6]...) # this is equivalent to add(5,6) -x = (1,2,3) # => (1,2,3) -Set(x) # => Set{(Int64,Int64,Int64)}((1,2,3)) # a Set of Tuples -Set(x...) # => Set{Int64}(2,3,1) +x = (5,6) # => (5,6) +add(x...) # this is equivalent to add(5,6) # You can define functions with optional positional arguments @@ -531,12 +547,8 @@ abstract Cat # 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 -subtypes(Number) # => 6-element Array{Any,1}: - # Complex{Float16} - # Complex{Float32} - # Complex{Float64} +subtypes(Number) # => 2-element Array{Any,1}: # Complex{T<:Real} - # ImaginaryUnit # Real subtypes(Cat) # => 0-element Array{Any,1} @@ -554,10 +566,11 @@ subtypes(AbstractString) # 8-element Array{Any,1}: # Every type has a super type; use the `super` function to get it. typeof(5) # => Int64 super(Int64) # => Signed -super(Signed) # => Real +super(Signed) # => Integer +super(Integer) # => Real super(Real) # => Number super(Number) # => Any -super(super(Signed)) # => Number +super(super(Signed)) # => Real super(Any) # => Any # All of these type, except for Int64, are abstract. typeof("fire") # => ASCIIString @@ -723,7 +736,7 @@ code_native(square_area, (Float64,)) # ret # # Note that julia will use floating point instructions if any of the -# arguements are floats. +# 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 |