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?
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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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