preg_match()未知修饰符'['帮助 [英] preg_match() Unknown modifier '[' help

问题描述

我有这个正则表达式来获取YouTube视频ID:

I have this regex for getting the YouTube video ID:

(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=[0-9]/)[^&\n]+|(?<=v=)[^&\n]+

我从那里得到它:用于解析youtube yid的正则表达式

问题是我收到preg_match() Unknown modifier '['警告.

我知道我必须封装正则表达式定界符，但是我不知道该怎么做.

I know I have to enclose the regex delimiters but I have no idea how to do this.

有帮助吗?

推荐答案

尝试以下操作:

<?php
  $str = "http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I";
  $pattern = '#(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=[0-9]/)[^&\n]+|(?<=v=)[^&\n]+#';
  preg_match($pattern, $str, $matches); 
  print_r($matches);
?>

请注意，我在这里使用#作为分隔符只是因为上面的正则表达式包含正斜杠，而转义它们会使表达式更难以阅读.这样可以清理几个像素.

Note, I'm using # as a delimiter here simply because the regular expression above contains forward slashes and escaping them makes the expression more difficult to read. This cleans it up by just a few pixels.

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