php 语法 $a = $b = 1;

Question

是

$a = 1;
$b = $a;

等于写这个？

$a = $b = 1;

第二个示例是否总是将 1 作为 $a 和 $b 的值，即使 $a 和 $b 已经分配了一个值？

Answer 1

Quoting the documentation:

The value of an assignment expression is the value assigned. That is, the value of "$a = 3" is 3. This allows you to do some tricky things:

<?php

$a = ($b = 4) + 5; // $a is equal to 9 now, and $b has been set to 4.

?>

所以，为了回答您的问题，赋值 $b = 1 的结果是 1，因此，$a = $b = 1 将赋值$b = 1——也就是1——到$a.

话虽如此，滥用它会导致代码难以阅读。