如何访问字符串的特定部分并在php中处理后替换它

我有一串这样的东西

$text_string = 'Every thing must be done in time. So,It is not a good thing to be
                so late. What are the Rules of This Process are prominent in this
                video [VIDEO]http://www.youtube.com/watch?v=yseAuiSl[/VIDEO]. So,
                It will be more sensible if you watch a tutorial here
                [VIDEO]http://www.dailymotion.com/video/xyxmu6_underwater[/VIDEO]
                It is much more explanatory. These are the Rules of Thumb.'

我需要得到每个

[视频]。。。。[/VIDEO]

然后将其传递给一个函数（我自己创建了该函数），该函数会将其转换为相应的嵌入代码

[VIDEO]http://www.youtube.com/watch?v=yseAuiSl[/VIDEO]

将转换为

<iframe width="680" height="450" src="http://www.youtube.com/embed/yseAuiSl" 
frameborder="0" allowfullscreen></iframe>

然后我需要替换

[视频]。。。。[/VIDEO]

及其嵌入代码。那么，我如何循环整个字符串并获得每个

[VIDEO]。。。[/VIDEO]

逐个标记，并在处理后将其替换为嵌入代码

echo preg\u replace（'/\[VIDEO\]（.+？）\[\/VIDEO\]/i'，''.$text\u字符串）；
echo preg_replace('/\[VIDEO\](.+?)\[\/VIDEO\]/i', '<iframe width="680" height="450" src="\\1" frameborder="0" allowfullscreen></iframe>', $text_string);

在我看来： 你需要反复阅读单词，找到视频的开始和结束位置； 一些代码：

$text_string = 'Every thing must be done in time. So,It is not a good thing to be
                so late. What are the Rules of This Process are prominent in this
                video [VIDEO]http://www.youtube.com/watch?v=yseAuiSl[/VIDEO]. So,
                It will be more sensible if you watch a tutorial here
                [VIDEO]http://www.dailymotion.com/video/xyxmu6_underwater[/VIDEO]
                It is much more explanatory. These are the Rules of Thumb.'

$start = '[VIDEO]';
$end = '[/VIDEO]';
$words_array  = explode(' ',$text_string);
$words = array_flip($words_array);

//Then you can check for video element with:
$word_pos = 0;
foreach($words as $the_word){
$word_pos++;
if ($the_word == $start){
$start_point = $word_pos;
}

if ($the_word == $end){
$end_point = $word_pos;
}
}
$video_link = echo substr($text_string,$start_point,$end_point);

---

该代码只是为了分享我的概念，这

花了很多时间，在Stackoverflow的帮助下，我找到了解决方案

$text_string = 'Every thing must be done in time. So,It is not a good thing to be
                so late. What are the Rules of This Process are prominent in this
                video [VIDEO]http://www.youtube.com/watch?v=yseAuiSl[/VIDEO]. So,
                It will be more sensible if you watch a tutorial here
                [VIDEO]http://www.dailymotion.com/video/xyxmu6_underwater[/VIDEO]
                It is much more explanatory. These are the Rules of Thumb.'

下面是将我的链接转换为嵌入代码的函数

function convert_to_embed($matches) {
  $link = $matches[1];

  // All the Function Process

  return $embed;
}

这里我使用的是

preg\u replace\u callback

函数，该函数将逐个处理每个视频标记，该函数将转换视频标记并用其嵌入代码替换

 $finalized_string  = preg_replace_callback('/\[VIDEO\](.+?)\[\/VIDEO\]/i', "convert_to_embed", $text_string);

---

@Charlie，这只是为了替换，但是首先我需要得到整个视频标签，通过一个函数处理它，然后用它的输出替换它。那么，如何从字符串中提取每个视频标记呢？使用

preg\u match（）

->处理->

preg\u replace（）

。祝你好运google:php替换标签虽然，我必须处理视频标签之间的链接，但是我从你的preg_替换中得到了一个想法。我将使用preg_replace_回调。谢谢你的正则表达式。