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Analysis of the difference between three equal signs '===' and two equal signs '==' in PHP

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Release： 2016-07-25 08:57:04

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Let’s analyze the difference between three equal signs === and two equal signs == in PHP. Friends in need can refer to it.

Recently, I want to study the specific difference between "===" and "==" in PHP. In fact, "===" is also used for comparison, but the comparison requirements are more stringent. It will require that the types on both sides are the same;

For example:

When $a=8; if($a==8.0) or if($a==8) both return TRUE; But if($a===8.0) returns false, because the two types are different, only if($a===8) returns true;

Suppose, a function will return the following situations: 1. Numbers greater than 0 2. Numbers less than 0 3. A number equal to 0 (that is, 0) 4. False (on failure) At this time, if you need to capture the failure situation, you must use === instead of ==. why? Because == will not only match the 4th situation, but also the 3rd situation, because 0 is also false.

Related labels：

PHP中三个等号”===”与两个等号”==”的区别分析

source：php.cn

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