匹配字符串时，regex如何忽略转义引号？ [英] How can regex ignore escaped-quotes when matching strings?

问题描述

我正在尝试编写一个正则表达式，它将匹配一切，但是没有被转义的撇号。考虑以下内容：

 <？php $ s ='大家好，我们现在就准备好了。 ？> 
  

我的目标是编写一个正则表达式，它将基本上匹配它的字符串部分。我正在想一些例如

  /.*'（[^']）。* / 
  

为了匹配一个简单的字符串，但我一直在努力弄清楚如何得到一个负面的lookbehind工作在撇号以确保它之前没有反斜杠...

任何想法？

- JMT

解决方案

 <？php 
 $ backslash ='\\' ; 
 
 $ pattern =<<<< PATTERN 
＃（[：']）（？：{$ backslash} {$反斜杠}？+。）*？{$反斜杠} 1＃
 PATTERN; 
 
 foreach （array（
<？php \ $ s ='大家好，我们现在就准备好了''？''，
'<？php $ s = 大家好，我们现在就准备好了;？>'，
xyz'a\\'bc\\d'123，
x ='我的字符串以反斜杠\\\\';
）为$ subject结束; {
 preg_match（$ pattern，$ subject，$ matches）; 
 echo $ subject，'=> '，$ matches [0]，\\\
\\\
; 
} 
  

打印

 <？php $ s ='大家好，我们现在就准备好了。 ？> => 大家好，我们现在就准备好了
 
<？php $ s =大家好，我们现在就准备好了;？> =>大家，我们现在就准备好了。 
 
 xyz'a\'bc\d'123 => 'a\'bc\d'
 
 x ='我的字符串以反斜杠\\'结尾; => '我的字符串以反斜杠\\''
  

结束

I'm trying to write a regex that will match everything BUT an apostrophe that has not been escaped. Consider the following:

<?php $s = 'Hi everyone, we\'re ready now.'; ?>

My goal is to write a regular expression that will essentially match the string portion of that. I'm thinking of something such as

/.*'([^']).*/

in order to match a simple string, but I've been trying to figure out how to get a negative lookbehind working on that apostrophe to ensure that it is not preceded by a backslash...

Any ideas?

- JMT

解决方案

<?php
$backslash = '\\';

$pattern = <<< PATTERN
#(["'])(?:{$backslash}{$backslash}?+.)*?{$backslash}1#
PATTERN;

foreach(array(
    "<?php \$s = 'Hi everyone, we\\'re ready now.'; ?>",
    '<?php $s = "Hi everyone, we\\"re ready now."; ?>',
    "xyz'a\\'bc\\d'123",
    "x = 'My string ends with with a backslash\\\\';"
    ) as $subject) {
        preg_match($pattern, $subject, $matches);
        echo $subject , ' => ', $matches[0], "\n\n";
}

prints

<?php $s = 'Hi everyone, we\'re ready now.'; ?> => 'Hi everyone, we\'re ready now.'

<?php $s = "Hi everyone, we\"re ready now."; ?> => "Hi everyone, we\"re ready now."

xyz'a\'bc\d'123 => 'a\'bc\d'

x = 'My string ends with with a backslash\\'; => 'My string ends with with a backslash\\'

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