这个'/ /'和'~~'以及PHP正则表达式中的'##'有什么区别？ [英] What is the difference between this '/ /' and this '~ ~' and this '# #' in PHP regular expressions?

问题描述

您好我忘记了我在哪里找到了这个但是我遇到了这三个例子，我很尴尬他们产生了相同的输出。这3个例子意味着同样的事情吗？

所有这些之间有什么区别？我熟悉最后一个而不是其他两个。

Hello I forgot where I found this at but I ran into these 3 examples which I'm very
confused about they produce the same output. Do these 3 examples mean the same thing?
What's the difference between all of them? And I am familiar with the last one but not the other two.

<?php
$string = 'I have 2 dogs.';
if(preg_match('~\d~',$string))
{
echo 'The string above contains a numeric character.';
}
else
{
echo 'The string above does not contain a numeric character.';
}
?>

<?php
$string = 'I have 2 dogs.';
if(preg_match('#\d#',$string))
{
echo 'The string above contains a numeric character.';
}
else
{
echo 'The string above does not contain a numeric character.';
}
?>

<?php
$string = 'I have 2 dogs.';
if(preg_match('/\d/',$string))
{
echo 'The string above contains a numeric character.';
}
else
{
echo 'The string above does not contain a numeric character.';
}
?>

我尝试了什么：



谷歌没有我想要的东西所以我想我会在这里得到一个直接答案。

What I have tried:

Google did not have what I was looking for so I thought I'll get a direct answer here.

推荐答案

string ='我有2只狗。';
if（preg_match（'〜\d~'，

string = 'I have 2 dogs.'; if(preg_match('~\d~',

string））
{
echo'上面的字符串包含一个数字字符。' ;
}
else
{
echo'上面的字符串不包含数字字符。';
}
？>

string)) { echo 'The string above contains a numeric character.'; } else { echo 'The string above does not contain a numeric character.'; } ?>

<?php

string ='我有2只狗。';
if（preg_match（'＃\d＃'，

string = 'I have 2 dogs.'; if(preg_match('#\d#',

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