理解php中的三元运算符 [英] understading the ternary operator in php

问题描述

我正在阅读别人的代码，他们有这样一行:

I'm reading someone else's code and they have a line like this:

  $_REQUEST[LINKEDIN::_GET_TYPE] = (isset($_REQUEST[LINKEDIN::_GET_TYPE])) ? $_REQUEST[LINKEDIN::_GET_TYPE] : '';

我只想确保我遵循此规则.我可能最终已经弄清楚了它的逻辑.

I just want to make sure I follow this. I might have finally figured out the logic of it.

这是正确的吗?

如果设置了$_REQUEST[LINKEDIN::_GET_TYPE]，则将其分配给自己. (意味着什么都不做)，否则将其设置为空字符串. (这将暗示在脚本的其他部分中，NULL(未定义)和"将不会被视为相同.)

If $_REQUEST[LINKEDIN::_GET_TYPE] is set, then assign it to itself. (meant as a do-nothing condition) otherwise set it to a null string. (Would imply that NULL (undefined) and "" would not be treated the same in some other part of the script.)

推荐答案

您发布的三元运算符的作用类似于单行if-else，如下所示

The ternary operator you posted acts like a single line if-else as follows

if (isset($_REQUEST[LINKEDIN::_GET_TYPE])) {
  $_REQUEST[LINKEDIN::_GET_TYPE] = $_REQUEST[LINKEDIN::_GET_TYPE];
} else {
  $_REQUEST[LINKEDIN::_GET_TYPE] = '';
}

您可以简化为

if (!(isset($_REQUEST[LINKEDIN::_GET_TYPE]))) {
  $_REQUEST[LINKEDIN::_GET_TYPE] = '';
}

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