In the previous article "Let me tell you why require_once() in PHP is not easy to use! 》Introduced to you the reasons why require_once() in PHP is not easy to use. Friends who are interested can read and find out~
Then this article will introduce to you # in PHP Why is the ##=== operator faster than
==?
The === and == operators in PHP are comparison operators in PHP. The
operator is called which is absolutely equal to
, and the ==
operator is called which is equal to
. Syntax example:
, TRUE if $a is equal to $b after type conversion;
, if $a is equal to $b, and the two types are the same, it is TRUE;
<?php
var_dump(0 == "a");
// 1 == 1 -> true
var_dump("1" == "01");
// 10 == 10 -> true
var_dump("10" == "1e1");
// 100 == 100 -> true
var_dump(100 == "1e2");
var_dump(0 === "a");
// "1" === "01" -> false
var_dump("1" === "01");
// "10" === "1e1" -> false
var_dump("10" === "1e1");
// 100 == "1e2" -> false
var_dump(100 === "1e2");
switch ("a") {
case 0:
echo "第一种情况";
break;
case "a":
echo "第二种情况";
break;
}
boolean true boolean true boolean true boolean true boolean false boolean false boolean false boolean false 第一种情况
<?php var_dump(1 == TRUE); var_dump(0 == FALSE); var_dump(1 === TRUE); var_dump(0 === FALSE);
boolean true boolean true boolean false boolean false
Note: The === operator performs a "type-safe comparison", it will return true only if the two operands have the same type and value, and if only To compare values, use ==.
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