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Update output for Julia 1.0

This commit is contained in:
0u0 2018-08-31 09:43:02 +08:00
parent 35215e4a2d
commit 5691fb7a8d

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@ -89,7 +89,9 @@ false
# Strings are UTF8 encoded. Only if they contain only ASCII characters can # Strings are UTF8 encoded. Only if they contain only ASCII characters can
# they be safely indexed. # 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). # Otherwise, iterating over strings is recommended (map, for loops, etc).
# $ can be used for string interpolation: # $ 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 @printf "%d is less than %f\n" 4.5 5.3 # => 5 is less than 5.300000
# Printing is easy # 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 # String can be compared lexicographically
"good" > "bye" # => true "good" > "bye" # => true
@ -147,19 +149,18 @@ SomeOtherVar123! = 6 # => 6
# functions are sometimes called mutating functions or in-place functions. # functions are sometimes called mutating functions or in-place functions.
# Arrays store a sequence of values indexed by integers 1 through n: # 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. # 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 Array{Int64,1}: [4, 5, 6]
b = [4; 5; 6] # => 3-element Int64 Array: [4, 5, 6] b = [4; 5; 6] # => 3-element Array{Int64,1}: [4, 5, 6]
b[1] # => 4
b[end] # => 6 b[end] # => 6
# 2-dimensional 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] matrix = [1 2; 3 4] # => 2×2 Array{Int64,2}: [1 2; 3 4]
# Arrays of a particular type # 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! # Add stuff to the end of a list with push! and append!
push!(a, 1) # => [1] 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 # Function names that end in exclamations points indicate that they modify
# their argument. # 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 still [5,4,6]
sort!(arr) # => [4,5,6]; arr is now [4,5,6] 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 # Looking out of bounds is a BoundsError
try try
a[0] a[0]
# => BoundsError: attempt to access 7-element Array{Int64,1} at index [0] # => ERROR: BoundsError: attempt to access 7-element Array{Int64,1} at
a[end + 1] # index [0]
# => 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: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 catch e
println(e) println(e)
end end
@ -205,7 +218,8 @@ end
# find these files. # find these files.
# You can initialize arrays from ranges # 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. # You can look at ranges with slice syntax.
a[1:3] # => [1, 2, 3] 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, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple.
tup[1] # => 1 tup[1] # => 1
try 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 catch e
println(e) println(e)
end end
@ -254,11 +270,12 @@ e, d = d, e # => (5,4) # d is now 5 and e is now 4
# Dictionaries store mappings # 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 # 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{String,Int64} # => Dict{String,Int64} with 3 entries:
# => "two" => 2, "one" => 1, "three" => 3
# Look up values with [] # Look up values with []
filled_dict["one"] # => 1 filled_dict["one"] # => 1
@ -266,12 +283,13 @@ filled_dict["one"] # => 1
# Get all keys # Get all keys
keys(filled_dict) keys(filled_dict)
# => Base.KeySet for a Dict{String,Int64} with 3 entries. Keys: # => 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. # Note - dictionary keys are not sorted or in the order you inserted them.
# Get all values # Get all values
values(filled_dict) 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. # Note - Same as above regarding key ordering.
# Check for existence of keys in a dictionary with in, haskey # 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 # Trying to look up a non-existent key will raise an error
try try
filled_dict["four"] # => KeyError: key "four" not found filled_dict["four"] # => ERROR: KeyError: key "four" not found
catch e catch e
println(e) println(e)
end end
@ -293,7 +311,7 @@ get(filled_dict, "one", 4) # => 1
get(filled_dict, "four", 4) # => 4 get(filled_dict, "four", 4) # => 4
# Use Sets to represent collections of unordered, unique values # Use Sets to represent collections of unordered, unique values
empty_set = Set() # => Set{Any}() empty_set = Set() # => Set(Any[])
# Initialize a set with values # Initialize a set with values
filled_set = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1]) 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 from, to = pair
println("$from is a $to") println("$from is a $to")
end end
# prints: # => mouse is a mammal
# dog is a mammal # => cat is a mammal
# cat is a mammal # => dog is a mammal
# mouse is a mammal
for (k, v) in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal") for (k, v) in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal")
println("$k is a $v") println("$k is a $v")
end end
# prints: # => mouse is a mammal
# dog is a mammal # => cat is a mammal
# cat is a mammal # => dog is a mammal
# mouse is a mammal
# While loops loop while a condition is true # While loops loop while a condition is true
let x = 0 let x = 0
@ -406,11 +422,11 @@ end
add(5, 6) # => 11 after printing out "x is 5 and y is 6" add(5, 6) # => 11 after printing out "x is 5 and y is 6"
# Compact assignment of functions # Compact assignment of functions
f_add(x, y) = x + y # => "f (generic function with 1 method)" f_add(x, y) = x + y # => f_add (generic function with 1 method)
f_add(3, 4) # => 7 f_add(3, 4) # => 7
# Function can also return multiple values as tuple # Function can also return multiple values as tuple
fn(x, y) = x + y, x - y fn(x, y) = x + y, x - y # => fn (generic function with 1 method)
fn(3, 4) # => (7, -1) fn(3, 4) # => (7, -1)
# You can define functions that take a variable number of # You can define functions that take a variable number of
@ -437,13 +453,14 @@ add(x...) # this is equivalent to add(5,6)
function defaults(a, b, x=5, y=6) function defaults(a, b, x=5, y=6)
return "$a $b and $x $y" return "$a $b and $x $y"
end end
# => defaults (generic function with 3 methods)
defaults('h', 'g') # => "h g and 5 6" defaults('h', 'g') # => "h g and 5 6"
defaults('h', 'g', 'j') # => "h g and j 6" defaults('h', 'g', 'j') # => "h g and j 6"
defaults('h', 'g', 'j', 'k') # => "h g and j k" defaults('h', 'g', 'j', 'k') # => "h g and j k"
try try
defaults('h') # => ERROR: no method defaults(Char,) defaults('h') # => ERROR: MethodError: no method matching defaults(::Char)
defaults() # => ERROR: no methods defaults() defaults() # => ERROR: MethodError: no method matching defaults()
catch e catch e
println(e) println(e)
end end
@ -452,10 +469,11 @@ end
function keyword_args(;k1=4, name2="hello") # note the ; function keyword_args(;k1=4, name2="hello") # note the ;
return Dict("k1" => k1, "name2" => name2) return Dict("k1" => k1, "name2" => name2)
end end
# => keyword_args (generic function with 1 method)
keyword_args(name2="ness") # => ["name2"=>"ness","k1"=>4] keyword_args(name2="ness") # => ["name2"=>"ness", "k1"=>4]
keyword_args(k1="mine") # => ["k1"=>"mine","name2"=>"hello"] keyword_args(k1="mine") # => ["name2"=>"hello", "k1"=>"mine"]
keyword_args() # => ["name2"=>"hello","k1"=>4] keyword_args() # => ["name2"=>"hello", "k1"=>4]
# You can combine all kinds of arguments in the same function # You can combine all kinds of arguments in the same function
function all_the_args(normal_arg, optional_positional_arg=2; keyword_arg="foo") 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("optional arg: $optional_positional_arg")
println("keyword arg: $keyword_arg") println("keyword arg: $keyword_arg")
end end
# => all_the_args (generic function with 2 methods)
all_the_args(1, 3, keyword_arg=4) all_the_args(1, 3, keyword_arg=4)
# prints: # prints:
@ -477,6 +496,7 @@ function create_adder(x)
end end
return adder return adder
end end
# => create_adder (generic function with 1 method)
# This is "stabby lambda syntax" for creating anonymous functions # This is "stabby lambda syntax" for creating anonymous functions
(x -> x > 2)(3) # => true (x -> x > 2)(3) # => true
@ -485,6 +505,7 @@ end
function create_adder(x) function create_adder(x)
y -> x + y y -> x + y
end end
# => create_adder (generic function with 1 method)
# 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 create_adder(x)
@ -493,9 +514,11 @@ function create_adder(x)
end end
adder adder
end end
# => create_adder (generic function with 1 method)
add_10 = create_adder(10) add_10 = create_adder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64})
add_10(3) # => 13 # (generic function with 1 method)
add_10(3) # => 13
# There are built-in higher order functions # 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 using InteractiveUtils # defines the subtype and supertype function
# For example, Number is an abstract type # For example, Number is an abstract type
subtypes(Number) # => 2-element Array{Any,1}: subtypes(Number) # => 2-element Array{Any,1}:
# Complex{T<:Real} # => Complex
# 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 # 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 # => String
# SubString # => SubString
# SubstitutionString # => SubstitutionString
# Test.GenericString # => Test.GenericString
# Every type has a super type; use the `supertype` function to get it. # Every type has a super type; use the `supertype` function to get it.
typeof(5) # => Int64 typeof(5) # => Int64
@ -626,7 +649,7 @@ function meow(animal::Tiger)
end end
# Testing the meow function # Testing the meow function
meow(tigger) # => "rawwr" meow(tigger) # => "rawwwr"
meow(Lion("brown", "ROAAR")) # => "ROAAR" meow(Lion("brown", "ROAAR")) # => "ROAAR"
meow(Panther()) # => "grrr" meow(Panther()) # => "grrr"
@ -639,10 +662,11 @@ Panther <: Cat # => true
function pet_cat(cat::Cat) function pet_cat(cat::Cat)
println("The cat says $(meow(cat))") println("The cat says $(meow(cat))")
end 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 try
pet_cat(tigger) # => ERROR: no method pet_cat(Tiger,) pet_cat(tigger) # => ERROR: MethodError: no method matching pet_cat(::Tiger)
catch e catch e
println(e) println(e)
end end
@ -657,45 +681,54 @@ function fight(t::Tiger, c::Cat)
end end
# => fight (generic function with 1 method) # => fight (generic function with 1 method)
fight(tigger, Panther()) # => prints The orange tiger wins! fight(tigger, Panther()) # => The orange tiger wins!
fight(tigger, Lion("ROAR")) # => prints The orange tiger wins! fight(tigger, Lion("ROAR")) # => The orange tiger wins!
# Let's change the behavior when the Cat is specifically a Lion # 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 (generic function with 2 methods)
fight(tigger, Panther()) # => prints The orange tiger wins! fight(tigger, Panther()) # => The orange tiger wins!
fight(tigger, Lion("ROAR")) # => prints The green-maned lion wins! fight(tigger, Lion("ROAR")) # => The green-maned lion wins!
# We don't need a Tiger in order to fight # 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 (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 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 catch e
println(e) println(e)
# => MethodError(fight, (Panther("green"), Lion("green", "RAWR")),
# 0x000000000000557b)
end end
# Also let the cat go first # 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")
# => fight (generic function with 4 methods)
# This warning is because it's unclear which fight will be called in: # This warning is because it's unclear which fight will be called in:
try try
fight(Lion("RAR"), Lion("brown", "rarrr")) 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 catch e
println(e) println(e)
# => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")),
# 0x000000000000557c)
end end
# The result may be different in other versions of Julia # The result may be different in other versions of Julia
fight(l::Lion, l2::Lion) = println("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 # => fight (generic function with 5 methods)
fight(Lion("RAR"), Lion("brown", "rarrr")) # => The lions come to a tie
# Under the hood # Under the hood
@ -706,74 +739,112 @@ 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? # What happens when we feed square_area an integer?
code_native(square_area, (Int32,)) code_native(square_area, (Int32,), syntax = :intel)
# .section __TEXT,__text,regular,pure_instructions # .text
# Filename: none # ; Function square_area {
# Source line: 1 # Prologue # ; Location: REPL[116]:1 # Prologue
# push RBP # push rbp
# mov RBP, RSP # mov rbp, rsp
# Source line: 1 # ; Function *; {
# movsxd RAX, EDI # Fetch l from memory? # ; Location: int.jl:54
# imul RAX, RAX # Square l and store the result in RAX # imul ecx, ecx # Square l and store the result in ECX
# pop RBP # Restore old base pointer # ;}
# ret # Result will still be in RAX # 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,)) code_native(square_area, (Float32,), syntax = :intel)
# .section __TEXT,__text,regular,pure_instructions # .text
# Filename: none # ; Function square_area {
# Source line: 1 # ; Location: REPL[116]:1
# push RBP # push rbp
# mov RBP, RSP # mov rbp, rsp
# Source line: 1 # ; Function *; {
# vmulss XMM0, XMM0, XMM0 # Scalar single precision multiply (AVX) # ; Location: float.jl:398
# pop RBP # vmulss xmm0, xmm0, xmm0 # Scalar single precision multiply (AVX)
# ret # ;}
# 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]
# ;}
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
#
# Note that julia will use floating point instructions if any of the # Note that julia will use floating point instructions if any of the
# arguments are floats. # arguments are floats.
# Let's calculate the area of a circle # Let's calculate the area of a circle
circle_area(r) = pi * r * r # circle_area (generic function with 1 method) 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,)) code_native(circle_area, (Int32,), syntax = :intel)
# .section __TEXT,__text,regular,pure_instructions # .text
# Filename: none # ; Function circle_area {
# Source line: 1 # ; Location: REPL[121]:1
# push RBP # push rbp
# mov RBP, RSP # mov rbp, rsp
# Source line: 1 # ; Function *; {
# vcvtsi2sd XMM0, XMM0, EDI # Load integer (r) from memory # ; Location: operators.jl:502
# movabs RAX, 4593140240 # Load pi # ; Function *; {
# vmulsd XMM1, XMM0, QWORD PTR [RAX] # pi * r # ; Location: promotion.jl:314
# vmulsd XMM0, XMM0, XMM1 # (pi * r) * r # ; Function promote; {
# pop RBP # ; Location: promotion.jl:284
# ret # ; 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,)) code_native(circle_area, (Float64,), syntax = :intel)
# .section __TEXT,__text,regular,pure_instructions # .text
# Filename: none # ; Function circle_area {
# Source line: 1 # ; Location: REPL[121]:1
# push RBP # push rbp
# mov RBP, RSP # mov rbp, rsp
# movabs RAX, 4593140496 # movabs rax, 497711048
# Source line: 1 # ; Function *; {
# vmulsd XMM1, XMM0, QWORD PTR [RAX] # ; Location: operators.jl:502
# vmulsd XMM0, XMM1, XMM0 # ; Function *; {
# pop RBP # ; Location: promotion.jl:314
# ret # ; 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 ## Further Reading