运算符与记号

数学符号与函数的扩展文档在 [这里](@ref math-ops).

符号	含义
`@`	the at-sign marks a [macro](@ref man-macros) invocation; optionally followed by an argument list
`!`	感叹号是一个表示逻辑否定的前缀算符
`a!`	在函数名的末尾，`!` 用作表示函数会修改参数（或多个参数）
`#`	the number sign (or hash or pound) character begins single line comments
`#=`	when followed by an equals sign, it begins a multi-line comment (these are nestable)
`=#`	end a multi-line comment by immediately preceding the number sign with an equals sign
`$`	the dollar sign is used for [string](@ref string-interpolation) and [expression](@ref man-expression-interpolation) interpolation
[`%`](@ref rem)	the percent symbol is the remainder operator
`^`	the caret is the exponentiation operator
`&`	single ampersand is bitwise and
`&&`	double ampersands is short-circuiting boolean and
`\|`	single pipe character is bitwise or
`\|\|`	double pipe characters is short-circuiting boolean or
[`⊻`](@ref xor)	the unicode xor character is bitwise exclusive or
`~`	the tilde is an operator for bitwise not
`'`	a trailing apostrophe is the `adjoint` (that is, the complex transpose) operator Aᴴ
`*`	the asterisk is used for multiplication, including matrix multiplication and [string concatenation](@ref man-concatenation)
`/`	forward slash divides the argument on its left by the one on its right
`\`	backslash operator divides the argument on its right by the one on its left, commonly used to solve matrix equations
`()`	parentheses with no arguments constructs an empty `Tuple`
`(a,...)`	parentheses with comma-separated arguments constructs a tuple containing its arguments
`(a=1,...)`	parentheses with comma-separated assignments constructs a `NamedTuple`
`(x;y)`	parentheses can also be used to group one or more semicolon separated expressions
`a[]`	[array indexing](@ref man-array-indexing) (calling `getindex` or `setindex!`)
`[,]`	[vector literal constructor](@ref man-array-literals) (calling [`vect`](@ref Base.vect))
`[;]`	[vertical concatenation](@ref man-array-concatenation) (calling `vcat` or `hvcat`)
`[ ]`	with space-separated expressions, [horizontal concatenation](@ref man-concatenation) (calling `hcat` or `hvcat`)
`T{ }`	curly braces following a type list that type's [parameters](@ref Parametric-Types)
`{}`	curly braces can also be used to group multiple `where` expressions in function declarations
`;`	semicolons separate statements, begin a list of keyword arguments in function declarations or calls, or are used to separate array literals for vertical concatenation
`,`	commas separate function arguments or tuple or array components
`?`	the question mark delimits the ternary conditional operator (used like: `conditional ? if_true : if_false`)
`" "`	the single double-quote character delimits `String` literals
`""" """`	three double-quote characters delimits string literals that may contain `"` and ignore leading indentation
`' '`	the single-quote character delimits `Char` (that is, character) literals
` `	the backtick character delimits [external process](@ref Running-External-Programs) (`Cmd`) literals
`A...`	triple periods are a postfix operator that "splat" their arguments' contents into many arguments of a function call or declare a varargs function that "slurps" up many arguments into a single tuple
`a.b`	single periods access named fields in objects/modules (calling [`getproperty`](@ref Base.getproperty) or [`setproperty!`](@ref Base.setproperty!))
`f.()`	periods may also prefix parentheses (like `f.(...)`) or infix operators (like `.+`) to perform the function element-wise (calling `broadcast`)
`a:b`	colons (`:`) used as a binary infix operator construct a range from `a` to `b` (inclusive) with fixed step size `1`
`a:s:b`	colons (`:`) used as a ternary infix operator construct a range from `a` to `b` (inclusive) with step size `s`
`:`	when used by themselves, `Colon`s represent all indices within a dimension, frequently combined with [indexing](@ref man-array-indexing)
`::`	double-colons represent a type annotation or `typeassert`, depending on context, frequently used when declaring function arguments
`:( )`	quoted expression
`:a`	`Symbol` a
`<:`	子类型运算符
`>:`	supertype operator (reverse of subtype operator)
`=`	single equals sign is [assignment](@ref man-variables)
`==`	double equals sign is value equality comparison
`===`	triple equals sign is programmatically identical equality comparison
[`=>`](@ref Pair)	right arrow using an equals sign defines a `Pair` typically used to populate [dictionaries](@ref Dictionaries)
`->`	right arrow using a hyphen defines an [anonymous function](@ref man-anonymous-functions) on a single line
`	>`
`∘`	function composition operator (typed with \circ{tab}) combines two functions as though they are a single larger [function](@ref Function-composition-and-piping)