From 310fd066e91f454b990372ffa30e803cc8120975 Mon Sep 17 00:00:00 2001 From: Florian Merz Date: Thu, 11 Feb 2021 12:56:40 +0100 Subject: unslug zh-cn: move --- .../operators/assignment_operators/index.html | 413 --------------------- 1 file changed, 413 deletions(-) delete mode 100644 files/zh-cn/web/javascript/reference/operators/assignment_operators/index.html (limited to 'files/zh-cn/web/javascript/reference/operators/assignment_operators') diff --git a/files/zh-cn/web/javascript/reference/operators/assignment_operators/index.html b/files/zh-cn/web/javascript/reference/operators/assignment_operators/index.html deleted file mode 100644 index 66ae471cde..0000000000 --- a/files/zh-cn/web/javascript/reference/operators/assignment_operators/index.html +++ /dev/null @@ -1,413 +0,0 @@ ---- -title: 赋值运算符 -slug: Web/JavaScript/Reference/Operators/Assignment_Operators -tags: - - JavaScript - - 运算符 -translation_of: Web/JavaScript/Reference/Operators#Assignment_operators -translation_of_original: Web/JavaScript/Reference/Operators/Assignment_Operators ---- -
{{jsSidebar("Operators")}}
- -

赋值运算符（assignment operator）基于右值（right operand）的值，给左值（left operand）赋值。

- -
{{EmbedInteractiveExample("pages/js/expressions-assignment.html")}}
- - - -

概述

- -

基本的赋值运算符是等号（=），该运算符把它右边的运算值赋给左边。即，x = y 把 y 的值赋给 x。 其他的赋值运算符通常是标准运算符的简写形式，如下面的定义与示例。 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
名称简写形式含义
赋值（Assignment）x = yx = y
加赋值（Addition assignment）x += yx = x + y
减赋值（Subtraction assignment）x -= yx = x - y
乘赋值（Multiplication assigment）x *= yx = x * y
除赋值（Division assignment）x /= yx = x / y
模赋值（Remainder assignment）x %= yx = x % y
指数赋值（Exponentiation assignment）x **= yx = x ** y
左移赋值（Left shift assignment）x <<= yx = x << y
右移赋值（Right shift assignment）x >>= yx = x >> y
无符号右移赋值（Unsigned right shift assignment）x >>>= yx = x >>> y
按位与赋值（Bitwise AND assignment）x &= yx = x & y
按位异或赋值（Bitwise XOR assignment）x ^= yx = x ^ y
按位或赋值（Bitwise OR assignment）x |= yx = x | y
- -

赋值

- -

简单的赋值运算符，把一个值赋给一个变量。为了把一个值赋给多个变量，可以以链式使用赋值运算符。参考下例：

- -

语法

- -
Operator: x = y
-
- -

示例

- -
// Assuming the following variables
-//  x = 5
-//  y = 10
-//  z = 25
-
-x = y     // x is 10
-x = y = z // x, y and z are all 25
-
- -

加赋值（Addition assignment）

- -

加赋值运算符把一个右值与一个变量相加，然后把相加的结果赋给该变量。两个操作数的类型决定了加赋值运算符的行为。算术相加或字符串连接都有可能。更多细节参考 {{jsxref("Operators/Arithmetic_Operators", "addition operator", "#Addition", 1)}}。

- -

语法

- -
Operator: x += y
-Meaning:  x  = x + y
-
- -

示例

- -
// 定义下列变量
-//  foo = 'foo'
-//  bar = 5
-//  baz = true
-
-
-// Number + Number -> addition
-bar += 2 // 7
-
-// Boolean + Number -> addition
-baz += 1 // 2
-
-// Boolean + Boolean -> addition
-baz += false // 1
-
-// Number + String -> concatenation
-bar += 'foo' // "5foo"
-
-// String + Boolean -> concatenation
-foo += false // "foofalse"
-
-// String + String -> concatenation
-foo += 'bar' // "foobar"
-
- -

减赋值（Subtraction assignment）

- -

减赋值运算符使一个变量减去右值，然后把结果赋给该变量。更多细节查看 {{jsxref("Operators/Arithmetic_Operators", "subtraction operator", "#Subtraction", 1)}} 。

- -

语法

- -
Operator: x -= y
-Meaning:  x  = x - y
-
- -

示例

- -
// 假定已定义了下面的变量
-//  bar = 5
-
-bar -= 2     // 3
-bar -= "foo" // NaN
-
- -

乘赋值（Multiplication assignment）

- -

乘赋值运算符使一个变量乘以右值，然后把相成的结果赋给该变量。更多细节查看 {{jsxref("Operators/Arithmetic_Operators", "multiplication operator", "#Multiplication", 1)}}。

- -

语法

- -
Operator: x *= y
-Meaning:  x  = x * y
-
- -

示例

- -
// 假定已定义了下面的变量
-//  bar = 5
-
-bar *= 2     // 10
-bar *= 'foo' // NaN
-
- -

除赋值（Division assignment）

- -

除赋值运算符使一个变量除以右值，然后把结果赋给该变量。更多细节查看 {{jsxref("Operators/Arithmetic_Operators", "division operator", "#Division", 1)}}。

- -

语法

- -
Operator: x /= y
-Meaning:  x  = x / y
-
- -

示例

- -
// 假定已定义了下面的变量
-//  bar = 5
-
-bar /= 2     // 2.5
-bar /= "foo" // NaN
-bar /= 0     // Infinity
-
- -

模赋值（Remainder assignment）

- -

模赋值运算符使一个变量除以右值，然后把余数赋给该变量。更多细节查看 {{jsxref("Operators/Arithmetic_Operators", "remainder operator", "#Remainder", 1)}}。

- -

语法

- -
Operator: x %= y
-Meaning:  x  = x % y
-
- -

示例

- -
// Assuming the following variable
-//  bar = 5
-
-bar %= 2     // 1
-bar %= 'foo' // NaN
-bar %= 0     // NaN
-
- -

指数赋值（Exponentiation assignment）

- -

指数赋值运算符使一个变量为底数、以右值为指数的指数运算（乘方）结果赋给该变量。更多细节查看 {{jsxref("Operators/Arithmetic_Operators", "算术运算符", "#Exponentiation", 1)}}。

- -

语法

- -
语法: x **= y
-含义:  x  = x ** y
-
- -

示例

- -
// Assuming the following variable
-//  bar = 5
-
-bar **= 2     // 25
-bar **= 'foo' // NaN
- -

左移赋值（Left shift assignment）

- -

左移赋值运算符使变量向左移动指定位数的比特位，然后把结果赋给该变量。更多细节查看 {{jsxref("Operators/Bitwise_Operators", "left shift operator", "#Left_shift", 1)}}。

- -

语法

- -
Operator: x <<= y
-Meaning:  x   = x << y
-
- -

示例

- -
var bar = 5; //  (00000000000000000000000000000101)
-bar <<= 2; // 20 (00000000000000000000000000010100)
-
- -

右移赋值（Right shift assignment）

- -

右移赋值运算符使变量向右移指定位数的比特位，然后把结果赋给该变量。更多细节查看 {{jsxref("Operators/Bitwise_Operators", "right shift operator", "#Right_shift", 1)}}。

- -

语法

- -
Operator: x >>= y
-Meaning:  x   = x >> y
-
- -

示例

- -
var bar = 5; //   (00000000000000000000000000000101)
-bar >>= 2;   // 1 (00000000000000000000000000000001)
-
-var bar = -5; //    (-00000000000000000000000000000101)
-bar >>= 2;  // -2 (-00000000000000000000000000000010)
-
- -

无符号右移赋值（Unsigned right shift assignment）

- -

无符号右移赋值运算符向右移动指定数量的比特位，然后把结果赋给变量。更多细节查看 {{jsxref("Operators/Bitwise_Operators", " unsigned right shift operator", "#Unsigned_right_shift", 1)}}。

- -

语法

- -
Operator: x >>>= y
-Meaning:  x    = x >>> y
-
- -

示例

- -
var bar = 5; //   (00000000000000000000000000000101)
-bar >>>= 2;  // 1 (00000000000000000000000000000001)
-
-var bar = -5; // (-00000000000000000000000000000101)
-bar >>>= 2; // 1073741822 (00111111111111111111111111111110)
- -

按位与赋值（Bitwise AND assignment）

- -

按位与赋值运算符使用两个操作值的二进制表示，执行按位与运算，并把结果赋给变量。更多细节查看 {{jsxref("Operators/Bitwise_Operators", "bitwise AND operator", "#Bitwise_AND", 1)}}。

- -

语法

- -
Operator: x &= y
-Meaning:  x  = x & y
-
- -

示例

- -
var bar = 5;
-// 5:     00000000000000000000000000000101
-// 2:     00000000000000000000000000000010
-bar &= 2; // 0
-
- -

按位异或赋值（Bitwise XOR assignment）

- -

按位异或赋值运算符使用两个操作值的二进制表示，执行二进制异或运算，并把结果赋给变量。更多细节查看 {{jsxref("Operators/Bitwise_Operators", "bitwise XOR operator", "#Bitwise_XOR", 1)}}。

- -

语法

- -
Operator: x ^= y
-Meaning:  x  = x ^ y
-
- -

示例

- -
var bar = 5;
-bar ^= 2; // 7
-// 5: 00000000000000000000000000000101
-// 2: 00000000000000000000000000000010
-// -----------------------------------
-// 7: 00000000000000000000000000000111
-
- -

按位或赋值（Bitwise OR assignment）

- -

按位或赋值运算符使用两个操作值的二进制表示，执行按位或运算，并把结果赋给变量。更多细节查看 {{jsxref("Operators/Bitwise_Operators", "bitwise OR operator", "#Bitwise_OR", 1)}}。

- -

语法

- -
Operator: x |= y
-Meaning:  x  = x | y
-
- -

示例

- -
var bar = 5;
-bar |= 2; // 7
-// 5: 00000000000000000000000000000101
-// 2: 00000000000000000000000000000010
-// -----------------------------------
-// 7: 00000000000000000000000000000111
-
- -

示例

- -

带有赋值运算符的左值（Left operand）

- -

在某些不常见的情况下，赋值运算符（如 x += y）并不等同于表达式（ x = x + y）。当一个赋值运算符的左值包含有一个赋值运算符时，左值只会被求值一次。例如：

- -
a[i++] += 5         // i 执行一次求值
-a[i++] = a[i++] + 5 // i 执行两次求值
-
- -

规范

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ESDraft', '#sec-assignment-operators', 'Assignment operators')}}{{Spec2('ESDraft')}}
{{SpecName('ES2015', '#sec-assignment-operators', 'Assignment operators')}}{{Spec2('ES2015')}}
{{SpecName('ES5.1', '#sec-11.13', 'Assignment operators')}}{{Spec2('ES5.1')}}
{{SpecName('ES1', '#sec-11.13', 'Assignment operators')}}{{Spec2('ES1')}}Initial definition.
- -

浏览器兼容性

- - - -

{{Compat("javascript.operators.assignment")}}

- -

相关链接

- - -- cgit v1.2.3-54-g00ecf