diff options
| -rw-r--r-- | julia.html.markdown | 80 |
1 files changed, 49 insertions, 31 deletions
diff --git a/julia.html.markdown b/julia.html.markdown index e824bfcf..f8c2f6e7 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -274,22 +274,22 @@ get(filled_dict,"four",4) #=> 4 # Use Sets to represent collections of unordered, unique values empty_set = Set() #=> Set{Any}() -# Initialize a set with a bunch of values +# Initialize a set with values filled_set = Set(1,2,2,3,4) #=> Set{Int64}(1,2,3,4) -# Add more items to a set +# Add more values to a set add!(filled_set,5) #=> Set{Int64}(5,4,2,3,1) +# Check if the values are in the set +contains(filled_set,2) #=> true +contains(filled_set,10) #=> 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) -# Check for existence in a set with contains -contains(filled_set,2) #=> true -contains(filled_set,10) #=> false - #################################################### ## 3. Control Flow @@ -298,8 +298,7 @@ contains(filled_set,10) #=> false # Let's make a variable some_var = 5 -# Here is an if statement. Indentation is NOT meaningful in Julia. -# prints "some var is smaller than 10" +# 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. @@ -307,44 +306,56 @@ elseif some_var < 10 # This elseif clause is optional. else # The else clause is optional too. println("some_var is indeed 10.") end +#=> prints "some var is smaller than 10" -# For loops iterate over iterables, such as ranges, lists, sets, dicts, strings. - +# For loops iterate over iterables. +# Iterable types include Range, Array, Set, Dict, and String. for animal=["dog", "cat", "mouse"] - # You can use $ to interpolate into strings 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 -# You can use in instead of =, if you want. +# You can use 'in' instead of '='. for animal in ["dog", "cat", "mouse"] println("$animal is a mammal") end +# prints: +# dog is a mammal +# cat is a mammal +# mouse is a mammal for a in ["dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal"] - println("$(a[1]) is $(a[2])") + println("$(a[1]) is a $(a[2])") end +# prints: +# dog is a mammal +# cat is a mammal +# mouse is a mammal for (k,v) in ["dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal"] - println("$k is $v") + println("$k is a $v") end - - -# While loops go until a condition is no longer met. # prints: -# 0 -# 1 -# 2 -# 3 +# dog is a mammal +# cat is a mammal +# 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 end +# prints: +# 0 +# 1 +# 2 +# 3 # Handle exceptions with a try/except block try @@ -359,11 +370,14 @@ end ## 4. Functions #################################################### -# Use the keyword function to create new functions +# The keyword 'function' creates new functions +#function name(arglist) +# body... +#end function add(x, y) println("x is $x and y is $y") - # Functions implicitly return the value of their last statement + # Functions return the value of their last statement x + y end @@ -373,13 +387,16 @@ add(5, 6) #=> 11 after printing out "x is 5 and y is 6" # positional arguments function varargs(args...) return args + # use the keyword return to return anywhere in the function end +#=> varargs (generic function with 1 method) varargs(1,2,3) #=> (1,2,3) # The ... is called a splat. -# It can also be used in a fuction call -# to splat a list or tuple out to be the arguments +# We just used it in a function definition. +# It can also be used in a fuction 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) @@ -412,7 +429,7 @@ keyword_args(name2="ness") #=> ["name2"=>"ness","k1"=>4] keyword_args(k1="mine") #=> ["k1"=>"mine","name2"=>"hello"] keyword_args() #=> ["name2"=>"hello","k2"=>4] -# You can also do both at once +# 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") @@ -433,12 +450,15 @@ function create_adder(x) return adder end -# or equivalently +# 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) y -> x + y end -# you can also name the internal function, if you want +# You can also name the internal function, if you want function create_adder(x) function adder(y) x + y @@ -449,14 +469,12 @@ end add_10 = create_adder(10) add_10(3) #=> 13 -# The first two inner functions above are anonymous functions -(x -> x > 2)(3) #=> true # 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] -# We can use list comprehensions for nice maps and filters +# 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] |