关于php的0，''，false，null引发的空字符串和空格的空字符串的思考

2020-10-29 17:46:45 16 日常记录 1447 16 百度已收录

关于php的0，空字符串，false，null引发的空字符串和空格的空字符串的思考，今天在业务开发中遇到一个有点意思的问题，在仔细思考下发现了很有意思的点，接下来出题

<?php
    $a = "";
    $b = " ";
    $c=trim($b);
    if($a==$b){
        var_dump('===');
    }else{
        var_dump("!=");
    }
    echo '<br>';
    if($a==$c){
        var_dump('===');
    }else{
        var_dump("!=");
    }
?>

以上为实例，不知道大家在初次遇到这个问题会怎么处理，是否会先入为主，而导致你业务出错，浪费宝贵时间。
以下为输出结果
eg:

string(2) "!="
string(3) "==="

我在没有仔细考虑这个问题的时候，一直认为，””、” “的区别，在肉眼上看，这个2个好像都是空字符串，可代码会告诉你，不，他们不一样，但是一定等你仔细看的时候，你一定就会发现，其中一个是因为多了一个空格，而在计算机的时间里，空格也是占用内存空间的，自然在语言处理中，也会进行区别对待。

所以任何事情都不能想当然，眼见不一定为实，一定要多思考，和实践。以下引用一下伟大领袖毛主席的话。

实践才是检验真理的唯一标准—-毛泽东

记录一次安装GITLAB的过程，好记性不如烂笔头。

Linux命令 == 查看系统负载 uptime命令详解

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