数组表示法中的 PHP 大括号

Question

我刚刚遇到了一段非常奇怪的 php 代码:

$oink{'pig'} = 1;
var_dump($oink);

$oink{'pig'} = '123123';
echo $oink{'pig'}; /* => 123123 */
echo $oink['pig']; /* => 123123 */

它像数组一样工作，但手册中没有提及。这是什么？

Answer 1

它是在手册中提到的。 {} 只是 [] § Accessing array elements with square bracket syntax 的替代语法.自 PHP 7.4.0 起不推荐使用此方法，自 PHP 8.0.0 起不再支持。

Note:

Prior to PHP 8.0.0, square brackets and curly braces could be used interchangeably for accessing array elements (e.g. $array[42] and $array{42} would both do the same thing in the example above). The curly brace syntax was deprecated as of PHP 7.4.0 and no longer supported as of PHP 8.0.0.

字符串 § String access and modification by character 也是如此:

Characters within strings may be accessed and modified by specifying the zero-based offset of the desired character after the string using square array brackets, as in $str[42]. Think of a string as an array of characters for this purpose. [...]

Note: Prior to PHP 8.0.0, strings could also be accessed using braces, as in $str{42}, for the same purpose. This curly brace syntax was deprecated as of PHP 7.4.0 and no longer supported as of PHP 8.0.0.