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-rw-r--r--zh-cn/julia-cn.html.markdown359
1 files changed, 203 insertions, 156 deletions
diff --git a/zh-cn/julia-cn.html.markdown b/zh-cn/julia-cn.html.markdown
index 1f91d52c..6c94aa2f 100644
--- a/zh-cn/julia-cn.html.markdown
+++ b/zh-cn/julia-cn.html.markdown
@@ -5,10 +5,11 @@ contributors:
- ["Jichao Ouyang", "http://oyanglul.us"]
translators:
- ["Jichao Ouyang", "http://oyanglul.us"]
+ - ["woclass", "https://github.com/inkydragon"]
lang: zh-cn
---
-```ruby
+```julia
# 单行注释只需要一个井号
#= 多行注释
只需要以 '#=' 开始 '=#' 结束
@@ -19,41 +20,41 @@ lang: zh-cn
## 1. 原始类型与操作符
####################################################
-# Julia 中一切皆是表达式。
-
-# 这是一些基本数字类型.
-3 # => 3 (Int64)
-3.2 # => 3.2 (Float64)
-2 + 1im # => 2 + 1im (Complex{Int64})
-2//3 # => 2//3 (Rational{Int64})
-
-# 支持所有的普通中缀操作符。
-1 + 1 # => 2
-8 - 1 # => 7
-10 * 2 # => 20
-35 / 5 # => 7.0
-5 / 2 # => 2.5 # 用 Int 除 Int 永远返回 Float
-div(5, 2) # => 2 # 使用 div 截断小数点
-5 \ 35 # => 7.0
-2 ^ 2 # => 4 # 次方, 不是二进制 xor
-12 % 10 # => 2
+# Julia 中一切皆为表达式
+
+# 这是一些基本数字类型
+typeof(3) # => Int64
+typeof(3.2) # => Float64
+typeof(2 + 1im) # => Complex{Int64}
+typeof(2 // 3) # => Rational{Int64}
+
+# 支持所有的普通中缀操作符
+1 + 1 # => 2
+8 - 1 # => 7
+10 * 2 # => 20
+35 / 5 # => 7.0
+10 / 2 # => 5.0 # 整数除法总是返回浮点数
+div(5, 2) # => 2 # 使用 div 可以获得整除的结果
+5 \ 35 # => 7.0
+2^2 # => 4 # 幂运算,不是异或 (xor)
+12 % 10 # => 2
# 用括号提高优先级
(1 + 3) * 2 # => 8
-# 二进制操作符
-~2 # => -3 # 非
-3 & 5 # => 1 # 与
-2 | 4 # => 6 # 或
-2 $ 4 # => 6 # 异或
-2 >>> 1 # => 1 # 逻辑右移
-2 >> 1 # => 1 # 算术右移
-2 << 1 # => 4 # 逻辑/算术 右移
-
-# 可以用函数 bits 查看二进制数。
-bits(12345)
+# 位操作符
+~2 # => -3 # 按位非 (not)
+3 & 5 # => 1 # 按位与 (and)
+2 | 4 # => 6 # 按位或 (or)
+xor(2, 4) # => 6 # 按位异或 (xor)
+2 >>> 1 # => 1 # 逻辑右移
+2 >> 1 # => 1 # 算术右移
+2 << 1 # => 4 # 逻辑/算术左移
+
+# 可以用函数 bitstring 查看二进制数。
+bitstring(12345)
# => "0000000000000000000000000000000000000000000000000011000000111001"
-bits(12345.0)
+bitstring(12345.0)
# => "0100000011001000000111001000000000000000000000000000000000000000"
# 布尔值是原始类型
@@ -61,17 +62,18 @@ true
false
# 布尔操作符
-!true # => false
-!false # => true
-1 == 1 # => true
-2 == 1 # => false
-1 != 1 # => false
-2 != 1 # => true
-1 < 10 # => true
-1 > 10 # => false
-2 <= 2 # => true
-2 >= 2 # => true
-# 比较可以串联
+!true # => false
+!false # => true
+1 == 1 # => true
+2 == 1 # => false
+1 != 1 # => false
+2 != 1 # => true
+1 < 10 # => true
+1 > 10 # => false
+2 <= 2 # => true
+2 >= 2 # => true
+
+# 链式比较
1 < 2 < 3 # => true
2 < 3 < 2 # => false
@@ -82,7 +84,8 @@ false
'a'
# 可以像取数组取值一样用 index 取出对应字符
-"This is a string"[1] # => 'T' # Julia 的 index 从 1 开始 :(
+ascii("This is a string")[1] # => 'T'
+# Julia 的 index 从 1 开始 :(
# 但是对 UTF-8 无效,
# 因此建议使用遍历器 (map, for loops, 等).
@@ -90,12 +93,18 @@ false
"2 + 2 = $(2 + 2)" # => "2 + 2 = 4"
# 可以将任何 Julia 表达式放入括号。
-# 另一种格式化字符串的方式是 printf 宏.
-@printf "%d is less than %f" 4.5 5.3 # 5 is less than 5.300000
+# 另一种输出格式化字符串的方法是使用标准库 Printf 中的 Printf 宏
+using Printf
+@printf "%d is less than %f\n" 4.5 5.3 # => 5 is less than 5.300000
# 打印字符串很容易
println("I'm Julia. Nice to meet you!")
+# 字符串可以按字典序进行比较
+"good" > "bye" # => true
+"good" == "good" # => true
+"1 + 2 = 3" == "1 + 2 = $(1 + 2)" # => true
+
####################################################
## 2. 变量与集合
####################################################
@@ -106,12 +115,12 @@ some_var # => 5
# 访问未声明变量会抛出异常
try
- some_other_var # => ERROR: some_other_var not defined
+ some_other_var # => ERROR: UndefVarError: some_other_var not defined
catch e
println(e)
end
-# 变量名需要以字母开头.
+# 变量名必须以下划线或字母开头
# 之后任何字母,数字,下划线,叹号都是合法的。
SomeOtherVar123! = 6 # => 6
@@ -122,7 +131,7 @@ SomeOtherVar123! = 6 # => 6
# 注意 Julia 的命名规约:
#
-# * 变量名为小写,单词之间以下划线连接('\_')。
+# * 变量名为小写,单词之间以下划线连接 "_" 。
#
# * 类型名以大写字母开头,单词以 CamelCase 方式连接。
#
@@ -131,57 +140,81 @@ SomeOtherVar123! = 6 # => 6
# * 会改变输入的函数名末位为 !。
# 这类函数有时被称为 mutating functions 或 in-place functions.
-# 数组存储一列值,index 从 1 开始。
-a = Int64[] # => 0-element Int64 Array
+# 数组存储一列值,index 从 1 开始
+a = Int64[] # => 0-element Array{Int64,1}
+
+# 一维数组可以以逗号分隔值的方式声明
+b = [4, 5, 6] # => 3-element Array{Int64,1}: [4, 5, 6]
+b = [4; 5; 6] # => 3-element Array{Int64,1}: [4, 5, 6]
+b[1] # => 4
+b[end] # => 6
-# 一维数组可以以逗号分隔值的方式声明。
-b = [4, 5, 6] # => 包含 3 个 Int64 类型元素的数组: [4, 5, 6]
-b[1] # => 4
-b[end] # => 6
+# 二维数组以分号分隔维度
+matrix = [1 2; 3 4] # => 2×2 Array{Int64,2}: [1 2; 3 4]
-# 二维数组以分号分隔维度。
-matrix = [1 2; 3 4] # => 2x2 Int64 数组: [1 2; 3 4]
+# 指定数组的类型
+b = Int8[4, 5, 6] # => 3-element Array{Int8,1}: [4, 5, 6]
# 使用 push! 和 append! 往数组末尾添加元素
-push!(a,1) # => [1]
-push!(a,2) # => [1,2]
-push!(a,4) # => [1,2,4]
-push!(a,3) # => [1,2,4,3]
-append!(a,b) # => [1,2,4,3,4,5,6]
+push!(a, 1) # => [1]
+push!(a, 2) # => [1,2]
+push!(a, 4) # => [1,2,4]
+push!(a, 3) # => [1,2,4,3]
+append!(a, b) # => [1,2,4,3,4,5,6]
-# 用 pop 弹出末尾元素
-pop!(b) # => 6 and b is now [4,5]
+# 用 pop 弹出尾部的元素
+pop!(b) # => 6
+b # => [4,5]
-# 可以再放回去
-push!(b,6) # b 又变成了 [4,5,6].
+# 再放回去
+push!(b, 6) # => [4,5,6]
+b # => [4,5,6]
-a[1] # => 1 # 永远记住 Julia 的 index 从 1 开始!
+a[1] # => 1 # 永远记住 Julia 的引索从 1 开始!而不是 0!
# 用 end 可以直接取到最后索引. 可用作任何索引表达式
a[end] # => 6
-# 还支持 shift 和 unshift
-shift!(a) # => 返回 1,而 a 现在时 [2,4,3,4,5,6]
-unshift!(a,7) # => [7,2,4,3,4,5,6]
+# 数组还支持 popfirst! 和 pushfirst!
+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]
# 以叹号结尾的函数名表示它会改变参数的值
-arr = [5,4,6] # => 包含三个 Int64 元素的数组: [5,4,6]
-sort(arr) # => [4,5,6]; arr 还是 [5,4,6]
-sort!(arr) # => [4,5,6]; arr 现在是 [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]
-# 越界会抛出 BoundsError 异常
+# 数组越界会抛出 BoundsError
try
- a[0] # => ERROR: BoundsError() in getindex at array.jl:270
- a[end+1] # => ERROR: BoundsError() in getindex at array.jl:270
+ a[0]
+ # => ERROR: BoundsError: attempt to access 7-element Array{Int64,1} at
+ # index [0]
+ # => 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
+ 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:196
catch e
println(e)
end
-# 错误会指出发生的行号,包括标准库
-# 如果你有 Julia 源代码,你可以找到这些地方
+# 报错时错误会指出出错的文件位置以及行号,标准库也一样
+# 你可以在 Julia 安装目录下的 share/julia 文件夹里找到这些标准库
# 可以用 range 初始化数组
-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]
# 可以切割数组
a[1:3] # => [1, 2, 3]
@@ -189,11 +222,13 @@ a[2:end] # => [2, 3, 4, 5]
# 用 splice! 切割原数组
arr = [3,4,5]
-splice!(arr,2) # => 4 ; arr 变成了 [3,5]
+splice!(arr, 2) # => 4
+arr # => [3,5]
# 用 append! 连接数组
b = [1,2,3]
-append!(a,b) # a 变成了 [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]
# 检查元素是否在数组中
in(1, a) # => true
@@ -201,162 +236,174 @@ in(1, a) # => true
# 用 length 获得数组长度
length(a) # => 8
-# Tuples 是 immutable 的
-tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple.
+# 元组(Tuples)是不可变的
+tup = (1, 2, 3) # => (1,2,3)
+typeof(tup) # => Tuple{Int64,Int64,Int64}
tup[1] # => 1
-try:
- tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64)
+try
+ tup[1] = 3
+ # => ERROR: MethodError: no method matching
+ # setindex!(::Tuple{Int64,Int64,Int64}, ::Int64, ::Int64)
catch e
println(e)
end
-# 大多数组的函数同样支持 tuples
+# 大多数组的函数同样支持元组
length(tup) # => 3
-tup[1:2] # => (1,2)
-in(2, tup) # => true
+tup[1:2] # => (1,2)
+in(2, tup) # => true
-# 可以将 tuples 元素分别赋给变量
-a, b, c = (1, 2, 3) # => (1,2,3) # a is now 1, b is now 2 and c is now 3
+# 可以将元组的元素解包赋给变量
+a, b, c = (1, 2, 3) # => (1,2,3)
+a # => 1
+b # => 2
+c # => 3
# 不用括号也可以
-d, e, f = 4, 5, 6 # => (4,5,6)
+d, e, f = 4, 5, 6 # => (4,5,6)
+d # => 4
+e # => 5
+f # => 6
# 单元素 tuple 不等于其元素值
(1,) == 1 # => false
-(1) == 1 # => true
+(1) == 1 # => true
# 交换值
-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
# 字典Dictionaries store mappings
-empty_dict = Dict() # => Dict{Any,Any}()
+empty_dict = Dict() # => Dict{Any,Any} with 0 entries
# 也可以用字面量创建字典
-filled_dict = ["one"=> 1, "two"=> 2, "three"=> 3]
-# => Dict{ASCIIString,Int64}
+filled_dict = Dict("one" => 1, "two" => 2, "three" => 3)
+# => Dict{String,Int64} with 3 entries:
+# => "two" => 2, "one" => 1, "three" => 3
# 用 [] 获得键值
filled_dict["one"] # => 1
# 获得所有键
keys(filled_dict)
-# => KeyIterator{Dict{ASCIIString,Int64}}(["three"=>3,"one"=>1,"two"=>2])
+# => Base.KeySet for a Dict{String,Int64} with 3 entries. Keys:
+# => "two", "one", "three"
# 注意,键的顺序不是插入时的顺序
# 获得所有值
values(filled_dict)
-# => ValueIterator{Dict{ASCIIString,Int64}}(["three"=>3,"one"=>1,"two"=>2])
+# => Base.ValueIterator for a Dict{String,Int64} with 3 entries. Values:
+# => 2, 1, 3
# 注意,值的顺序也一样
# 用 in 检查键值是否已存在,用 haskey 检查键是否存在
-in(("one", 1), filled_dict) # => true
-in(("two", 3), filled_dict) # => false
-haskey(filled_dict, "one") # => true
-haskey(filled_dict, 1) # => false
+in(("one" => 1), filled_dict) # => true
+in(("two" => 3), filled_dict) # => false
+haskey(filled_dict, "one") # => true
+haskey(filled_dict, 1) # => false
# 获取不存在的键的值会抛出异常
try
- filled_dict["four"] # => ERROR: key not found: four in getindex at dict.jl:489
+ filled_dict["four"] # => ERROR: KeyError: key "four" not found
catch e
println(e)
end
# 使用 get 可以提供默认值来避免异常
# get(dictionary,key,default_value)
-get(filled_dict,"one",4) # => 1
-get(filled_dict,"four",4) # => 4
+get(filled_dict, "one", 4) # => 1
+get(filled_dict, "four", 4) # => 4
-# 用 Sets 表示无序不可重复的值的集合
-empty_set = Set() # => Set{Any}()
-# 初始化一个 Set 并定义其值
-filled_set = Set(1,2,2,3,4) # => Set{Int64}(1,2,3,4)
+# Sets 表示无序不可重复的值的集合
+empty_set = Set() # => Set(Any[])
+# 初始化一个带初值的 Set
+filled_set = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1])
-# 添加值
-push!(filled_set,5) # => Set{Int64}(5,4,2,3,1)
+# 新增值
+push!(filled_set, 5) # => Set([4, 2, 3, 5, 1])
-# 检查是否存在某值
-in(2, filled_set) # => true
-in(10, filled_set) # => false
+# 检查 Set 中是否存在某值
+in(2, filled_set) # => true
+in(10, filled_set) # => false
# 交集,并集,差集
-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)
+other_set = Set([3, 4, 5, 6]) # => Set([4, 3, 5, 6])
+intersect(filled_set, other_set) # => Set([4, 3, 5])
+union(filled_set, other_set) # => Set([4, 2, 3, 5, 6, 1])
+setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set([4, 1])
####################################################
-## 3. 控制流
+## 3. 控制语句
####################################################
# 声明一个变量
some_var = 5
-# 这是一个 if 语句,缩进不是必要的
+# 这是一个 if 语句块,其中的缩进不是必须的
if some_var > 10
println("some_var is totally bigger than 10.")
-elseif some_var < 10 # elseif 是可选的.
+elseif some_var < 10 # elseif 是可选的
println("some_var is smaller than 10.")
-else # else 也是可选的.
+else # else 也是可选的
println("some_var is indeed 10.")
end
-# => prints "some var is smaller than 10"
+# => some_var is smaller than 10.
# For 循环遍历
-# Iterable 类型包括 Range, Array, Set, Dict, 以及 String.
-for animal=["dog", "cat", "mouse"]
+# 可迭代的类型包括:Range, Array, Set, Dict 和 AbstractString
+for animal = ["dog", "cat", "mouse"]
println("$animal is a mammal")
- # 可用 $ 将 variables 或 expression 转换为字符串into strings
+ # 你可以用 $ 将变量或表达式插入字符串中
end
-# prints:
-# dog is a mammal
-# cat is a mammal
-# mouse is a mammal
+# => dog is a mammal
+# => cat is a mammal
+# => mouse is a mammal
-# You can use 'in' instead of '='.
+# 你也可以不用 '=' 而使用 'in'
for animal in ["dog", "cat", "mouse"]
println("$animal is a mammal")
end
-# prints:
-# dog is a mammal
-# cat is a mammal
-# mouse is a mammal
+# => dog is a mammal
+# => cat is a mammal
+# => mouse is a mammal
-for a in ["dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal"]
- println("$(a[1]) is a $(a[2])")
+for pair in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal")
+ from, to = pair
+ println("$from is a $to")
end
-# prints:
-# dog is a mammal
-# cat is a mammal
-# mouse is a mammal
+# => mouse is a mammal
+# => cat is a mammal
+# => dog is a mammal
+# 注意!这里的输出顺序和上面的不同
-for (k,v) in ["dog"=>"mammal","cat"=>"mammal","mouse"=>"mammal"]
+for (k, v) in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal")
println("$k is a $v")
end
-# prints:
-# dog is a mammal
-# cat is a mammal
-# mouse is a mammal
+# => mouse is a mammal
+# => cat is a mammal
+# => dog is a mammal
# While 循环
-x = 0
-while x < 4
- println(x)
- x += 1 # x = x + 1
+let x = 0
+ while x < 4
+ println(x)
+ x += 1 # x = x + 1 的缩写
+ end
end
-# prints:
-# 0
-# 1
-# 2
-# 3
+# => 0
+# => 1
+# => 2
+# => 3
# 用 try/catch 处理异常
try
- error("help")
+ error("help")
catch e
- println("caught it $e")
+ println("caught it $e")
end
# => caught it ErrorException("help")