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浅析php中三个等号(===)和两个等号(==)的区别

Jun 06, 2016 pm 08:28 PM
php

以下是对php中三个等号(===)和两个等号(==)的区别进行了详细的分析介绍,需要的朋友可以过来参考下

先举个列子:
比如你一个函数会返回这几种情况:
1、大于0的数
2、小于0的数
3、等于0的数(也就是0啦)
4、False(失败时)
这时候如果你想捕获失败的情况,你就必须用===,而不能用==
因为==除了会匹配第4种情况外,还会匹配第3种情况,因为0也是假!

三个等号代表比较对象的类型也要一致。两个等号表示只要值相等就满足条件。

再来补充一些:
$a='2';//字符型2
$b=2;//数值型2
$a==$b,是对的,香港服务器,都是2
$a===$b,是不对的,美国服务器,因为$a是字符型$b是数值型,虚拟主机,值虽一样,但类型不一样。
还有就是“linvo1986 - 六级”说的那种“0”了。

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