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mirror of https://github.com/adambard/learnxinyminutes-docs.git synced 2025-08-11 17:24:29 +02:00

autoformat with VS code

mostly just spaces between arguments
This commit is contained in:
Martijn Visser
2018-08-14 18:00:00 +02:00
parent e9dd72024c
commit cf5cc6b76c

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@@ -31,7 +31,7 @@ This is based on Julia 1.0.0
3 # => 3 (Int64) 3 # => 3 (Int64)
3.2 # => 3.2 (Float64) 3.2 # => 3.2 (Float64)
2 + 1im # => 2 + 1im (Complex{Int64}) 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. # All of the normal infix operators are available.
1 + 1 # => 2 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 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 div(5, 2) # => 2 # for a truncated result, use div
5 \ 35 # => 7.0 5 \ 35 # => 7.0
2 ^ 2 # => 4 # power, not bitwise xor 2^2 # => 4 # power, not bitwise xor
12 % 10 # => 2 12 % 10 # => 2
# Enforce precedence with parentheses # Enforce precedence with parentheses
@@ -83,7 +83,7 @@ false
# Strings are created with " # Strings are created with "
try try
"This is a string." "This is a string."
catch ; end catch ; end
# Julia has several types of strings, including ASCIIString and UTF8String. # Julia has several types of strings, including ASCIIString and UTF8String.
@@ -91,19 +91,19 @@ catch ; end
# Character literals are written with ' # Character literals are written with '
try try
'a' 'a'
catch ; end catch ; end
# Some strings can be indexed like an array of characters # Some strings can be indexed like an array of characters
try try
"This is a string"[1] # => 'T' # Julia indexes from 1 "This is a string"[1] # => 'T' # Julia indexes from 1
catch ; end catch ; end
# However, this is will not work well for UTF8 strings, # However, this is will not work well for UTF8 strings,
# so iterating over strings is recommended (map, for loops, etc). # so iterating over strings is recommended (map, for loops, etc).
# $ can be used for string interpolation: # $ can be used for string interpolation:
try try
"2 + 2 = $(2 + 2)" # => "2 + 2 = 4" "2 + 2 = $(2 + 2)" # => "2 + 2 = 4"
catch ; end catch ; end
# You can put any Julia expression inside the parentheses. # 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 # String can be compared lexicographically
"good" > "bye" # => true "good" > "bye" # => true
"good" == "good" # => true "good" == "good" # => true
"1 + 2 = 3" == "1 + 2 = $(1+2)" # => true "1 + 2 = 3" == "1 + 2 = $(1 + 2)" # => true
#################################################### ####################################################
## 2. Variables and Collections ## 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] b = Int8[4, 5, 6] # => 3-element Int8 Array: [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]
push!(a,2) # => [1,2] push!(a, 2) # => [1,2]
push!(a,4) # => [1,2,4] push!(a, 4) # => [1,2,4]
push!(a,3) # => [1,2,4,3] push!(a, 3) # => [1,2,4,3]
append!(a,b) # => [1,2,4,3,4,5,6] append!(a, b) # => [1,2,4,3,4,5,6]
# Remove from the end with pop # 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 # 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! a[1] # => 1 # remember that Julia indexes from 1, not 0!
@@ -192,7 +192,7 @@ a[end] # => 6
# we also have shift and unshift # we also have shift and unshift
shift!(a) # => 1 and a is now [2,4,3,4,5,6] 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 # Function names that end in exclamations points indicate that they modify
# their argument. # their argument.
@@ -203,7 +203,7 @@ sort!(arr) # => [4,5,6]; arr is now [4,5,6]
# Looking out of bounds is a BoundsError # Looking out of bounds is a BoundsError
try try
a[0] # => ERROR: BoundsError() in getindex at array.jl:270 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 catch e
println(e) println(e)
end end
@@ -221,11 +221,11 @@ a[2:end] # => [2, 3, 4, 5]
# Remove elements from an array by index with splice! # Remove elements from an array by index with splice!
arr = [3,4,5] 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! # Concatenate lists with append!
b = [1,2,3] 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 # Check for existence in a list with in
in(1, a) # => true in(1, a) # => true
@@ -236,7 +236,7 @@ length(a) # => 8
# Tuples are immutable. # 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 tup[1] # => 1
try: 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 catch e
println(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}() empty_dict = Dict() # => Dict{Any,Any}()
# 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{ASCIIString,Int64} # => Dict{ASCIIString,Int64}
# Look up values with [] # Look up values with []
@@ -296,8 +296,8 @@ end
# Use the get method to avoid that error by providing a default value # 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, "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}()
@@ -305,7 +305,7 @@ empty_set = Set() # => Set{Any}()
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 # 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 # Check if the values are in the set
in(2, filled_set) # => true 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) other_set = Set([3, 4, 5, 6]) # => Set{Int64}(6,4,5,3)
intersect(filled_set, other_set) # => Set{Int64}(3,4,5) intersect(filled_set, other_set) # => Set{Int64}(3,4,5)
union(filled_set, other_set) # => Set{Int64}(1,2,3,4,5,6) 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. # For loops iterate over iterables.
# Iterable types include Range, Array, Set, Dict, and AbstractString. # Iterable types include Range, Array, Set, Dict, and AbstractString.
for animal=["dog", "cat", "mouse"] for animal = ["dog", "cat", "mouse"]
println("$animal is a mammal") println("$animal is a mammal")
# You can use $ to interpolate variables or expression into strings # You can use $ to interpolate variables or expression into strings
end end
@@ -356,7 +356,7 @@ end
# cat is a mammal # cat is a mammal
# mouse 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 $(a[2])") println("$(a[1]) is a $(a[2])")
end end
# prints: # prints:
@@ -364,7 +364,7 @@ end
# cat is a mammal # cat is a mammal
# mouse is a mammal # mouse is a mammal
for (k,v) in Dict("dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal") for (k, v) in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal")
println("$k is a $v") println("$k is a $v")
end end
# prints: # prints:
@@ -386,9 +386,9 @@ end
# Handle exceptions with a try/catch block # Handle exceptions with a try/catch block
try try
error("help") error("help")
catch e catch e
println("caught it $e") println("caught it $e")
end end
# => caught it ErrorException("help") # => caught it ErrorException("help")
@@ -426,7 +426,7 @@ function varargs(args...)
end end
# => varargs (generic function with 1 method) # => varargs (generic function with 1 method)
varargs(1,2,3) # => (1,2,3) varargs(1, 2, 3) # => (1,2,3)
# The ... is called a splat. # The ... is called a splat.
# We just used it in a function definition. # We just used it in a function definition.
@@ -434,18 +434,18 @@ varargs(1,2,3) # => (1,2,3)
# where it will splat an Array or Tuple's contents into the argument list. # where it will splat an Array or Tuple's contents into the argument list.
add([5,6]...) # this is equivalent to add(5,6) add([5,6]...) # this is equivalent to add(5,6)
x = (5,6) # => (5,6) x = (5, 6) # => (5,6)
add(x...) # this is equivalent to add(5,6) add(x...) # this is equivalent to add(5,6)
# You can define functions with optional positional arguments # You can define functions with optional positional arguments
function defaults(a,b,x=5,y=6) function defaults(a, b, x=5, y=6)
return "$a $b and $x $y" return "$a $b and $x $y"
end end
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: no method defaults(Char,)
defaults() # => ERROR: no methods defaults() defaults() # => ERROR: no methods defaults()
@@ -454,8 +454,8 @@ catch e
end end
# You can define functions that take keyword arguments # 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) return Dict("k1" => k1, "name2" => name2)
end end
keyword_args(name2="ness") # => ["name2"=>"ness","k1"=>4] 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] filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7]
# We can use list comprehensions for nicer maps # 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] [add_10(i) for i in [1, 2, 3]] # => [11, 12, 13]
#################################################### ####################################################
@@ -537,16 +537,16 @@ typeof(DataType) # => DataType
# ... # ...
# end # end
type Tiger type Tiger
taillength::Float64 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 end
# The default constructor's arguments are the properties # The default constructor's arguments are the properties
# of the type, in the order they are listed in the definition # 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 # 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 # These struct-style types are called concrete types
# They can be instantiated, but cannot have subtypes. # They can be instantiated, but cannot have subtypes.
@@ -588,19 +588,19 @@ supertype(DirectIndexString) # => AbstractString
# <: is the subtyping operator # <: is the subtyping operator
type Lion <: Cat # Lion is a subtype of Cat type Lion <: Cat # Lion is a subtype of Cat
mane_color mane_color
roar::AbstractString roar::AbstractString
end end
# You can define more constructors for your type # You can define more constructors for your type
# Just define a function of the same name as the 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 # 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 # 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 eye_color
Panther() = new("green") Panther() = new("green")
# Panthers will only have this constructor, and no default constructor. # Panthers will only have this constructor, and no default constructor.
end end
# Using inner constructors, like Panther does, gives you control # Using inner constructors, like Panther does, gives you control
@@ -619,30 +619,30 @@ end
# Definitions for Lion, Panther, Tiger # Definitions for Lion, Panther, Tiger
function meow(animal::Lion) function meow(animal::Lion)
animal.roar # access type properties using dot notation animal.roar # access type properties using dot notation
end end
function meow(animal::Panther) function meow(animal::Panther)
"grrr" "grrr"
end end
function meow(animal::Tiger) function meow(animal::Tiger)
"rawwwr" "rawwwr"
end end
# Testing the meow function # Testing the meow function
meow(tigger) # => "rawwr" meow(tigger) # => "rawwr"
meow(Lion("brown","ROAAR")) # => "ROAAR" meow(Lion("brown", "ROAAR")) # => "ROAAR"
meow(Panther()) # => "grrr" meow(Panther()) # => "grrr"
# Review the local type hierarchy # Review the local type hierarchy
issubtype(Tiger,Cat) # => false issubtype(Tiger, Cat) # => false
issubtype(Lion,Cat) # => true issubtype(Lion, Cat) # => true
issubtype(Panther,Cat) # => true issubtype(Panther, Cat) # => true
# Defining a function that takes Cats # Defining a function that takes Cats
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(Lion("42")) # => prints "The cat says 42" 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. # 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 # Let's define a function with more arguments, so we can see the difference
function fight(t::Tiger,c::Cat) function fight(t::Tiger, c::Cat)
println("The $(t.coatcolor) tiger wins!") println("The $(t.coatcolor) tiger wins!")
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()) # => prints The orange tiger wins!
fight(tigger,Lion("ROAR")) # => 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 # 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()) # => prints The orange tiger wins!
fight(tigger,Lion("ROAR")) # => prints The green-maned lion wins! fight(tigger, Lion("ROAR")) # => prints 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()) # => prints The victorious cat says grrr
try try
fight(Panther(),Lion("RAWR")) fight(Panther(), Lion("RAWR"))
catch e catch e
println(e) println(e)
# => MethodError(fight, (Panther("green"), Lion("green", "RAWR")), 0x000000000000557b) # => 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")
# 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")) # => prints The victorious cat says rarrr fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The victorious cat says rarrr
catch e catch e
println(e) println(e)
# => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")), 0x000000000000557c) # => 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(Lion("RAR"), Lion("brown", "rarrr")) # => prints The lions come to a tie
# Under the hood # Under the hood