diff options
| -rw-r--r-- | julia.html.markdown | 48 |
1 files changed, 33 insertions, 15 deletions
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) |