我有以下文本
"I made this video on my birthday. All of my friends are here in party. Click play to video the video
http://www.youtube.com/watch?v=G3j6avmJU48&feature=g-all-xit "
我想要的是将上面的url替换为
"I made this video on my birthday. All of my friends are here in party. Click play to video the video
<iframe width="853" height="480" src="http://www.youtube.com/embed/G3j6avmJU48" frameborder="0" allowfullscreen></iframe> "
我知道我们可以在下面的脚本中从上面的url获得youtube视频id
preg_match("#(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=v'/)[^&'n]+(?='?)|(?<=v=)[^&'n]+|(?<=youtu.be/)[^&'n]+#", $word, $matches);
$youtube_id = $matches[0];
但是我不知道如何替换url
http://www.youtube.com/watch?v=G3j6avmJU48&feature=g-all-xit
至
<iframe width="853" height="480" src="http://www.youtube.com/embed/G3j6avmJU48" frameborder="0" allowfullscreen></iframe>
请帮忙谢谢
使用preg_replace函数（请参阅PHP preg_replay（）文档）
编辑：
使用preg_replace如下：使用括号（）将要捕获的内容包装在regex中（第一个参数），然后在第二个参数中使用$n（n是regex中括号的顺序）来获取捕获的内容。
在你的情况下，你应该有这样的东西：
$text = "I made this video on my birthday. All of my friends are here in party. Click play to video the video http://www.youtube.com/watch?v=G3j6avmJU48&feature=g-all-xit";
$replaced = preg_replace('#http://www'.youtube'.com/watch'?v=('w+)[^'s]+#i','<iframe width="853" height="480" src="http://www.youtube.com/embed/$1" frameborder="0" allowfullscreen></iframe>',$text);
有关更高级的用法和示例，请参阅我之前为您提供的文档链接。
希望这对你有更多帮助。
编辑2:正则表达式错误，我修复了它。
您可以使用此示例代码来实现它，基于@mattcomment:
<?php
$text = "I made this video on my birthday. All of my friends are here in party. Click play to video the video
http://www.youtube.com/watch?v=G3j6avmJU48&feature=g-all-xit ";
$rexProtocol = '(https?://)?';
$rexDomain = '(www'.youtube'.com)';
$rexPort = '(:[0-9]{1,5})?';
$rexPath = '(/[!$-/0-9:;=@_'':;!a-zA-Z'x7f-'xff]*?)?';
$rexQuery = '('?[!$-/0-9:;=@_'':;!a-zA-Z'x7f-'xff]+?)?';
$rexFragment = '(#[!$-/0-9:;=@_'':;!a-zA-Z'x7f-'xff]+?)?';
function callback($match)
{
$completeUrl = $match[1] ? $match[0] : "http://{$match[0]}";
$videoId = array ();
preg_match ("|'?v=([a-zA-Z0-9]*)|", $match[5], $videoId);
return '<iframe src="http://www.youtube.com/embed/' . $videoId[1] . '" width="853" height="480"></iframe>';
}
print preg_replace_callback("&''b$rexProtocol$rexDomain$rexPort$rexPath$rexQuery$rexFragment(?=[?.!,;:'"]?('s|$))&", 'callback', htmlspecialchars($text));
?>