PHP的逻辑运算符是否可以像JavaScript一样工作? [英] Do PHP's logical operators work as JavaScript's?

问题描述

我最喜欢JavaScript的一件事是逻辑运算符非常强大:

One of the things I like the most of JavaScript is that the logical operators are very powerful:

• & 可用于安全地提取对象字段的值，如果该对象或字段尚未初始化，则将返回null

• && can be used to safely extract the value of an object's field, and will return null if either the object or the field has not been initialized

// returns null if param, param.object or param.object.field
// have not been set
field = param && param.object && param.object.field;

|| 可用于设置默认值:

// set param to its default value
param = param || defaultValue;

PHP是否也允许这种逻辑运算符的使用?

Does PHP allow this use of the logical operators as well?

推荐答案

PHP返回 true 或 false .但是您可以模拟JavaScript的 r = a ||b ||c 与:

PHP returns true orfalse. But you can emulate JavaScript's r = a || b || c with:

$r = $a ?: $b ?: $c;

关于与"，类似:

$r = ($a && $a->foo) ? $a->foo->bar : null;

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