PHP Regex不匹配`\\ [`

Question

I'm trying to write a regex to convert \\[#twitter:1234\\] into [#twitter:1234] ie unescape the square brackets for specific tags like Twitter, video, etc. I wrote up my expression and have tested it in Regex101 and PHPLiveRegex and it looks good but it still fails to get a match in my runtime. My actual implementation code is:

$content = preg_replace( "/\\\[#((?:twitter|video|instagram|cneembed):.*?)\\\]/i", "[#$1]", $content );

If anyone has any idea why the expression isn't working your guidance would be much appreciated. I'm generally pretty good at this stuff but I feel like I've gone blind on this one. I'm pretty certain the issue is how I'm escaping my backslashes since I can easily get the expression to match [#twitter:1234\\] just not the leading slash. Thanks!

Answer 1

问题在于，反斜杠既是字符串的转义字符，也是正则表达式的转义字符，因此您需要将所有反斜杠加倍以使它们传递到正则表达式引擎。

$content = preg_replace( "/\\\\\\[#((?:twitter|video|instagram|cneembed):.*?)\\\\\\]/i", "[#$1]", $content );