强大的Python来了

import pytube

yt = pytube.YouTube("https://www.youtube.com/watch?v=kwM2ApskJy4")

video_id = yt.video_id

print("video id from utl..",video_id)

虽然说得太晚了，但我已经把mantish和j-w的两个精彩回答搞混了。首先，修改后的正则表达式:

const youtube_regex = /^.*(youtu\.be\/|vi?\/|u\/\w\/|embed\/|\?vi?=|\&vi?=)([^#\&\?]*).*/

下面是测试代码(我已经将mantish的原始测试用例添加到j-w的更糟糕的测试用例中):

 var urls = [
      'http://www.youtube.com/watch?v=0zM3nApSvMg&feature=feedrec_grec_index',
      'http://www.youtube.com/user/IngridMichaelsonVEVO#p/a/u/1/QdK8U-VIH_o',
      'http://www.youtube.com/v/0zM3nApSvMg?fs=1&hl=en_US&rel=0',
      'http://www.youtube.com/watch?v=0zM3nApSvMg#t=0m10s',
      'http://www.youtube.com/embed/0zM3nApSvMg?rel=0',
      'http://www.youtube.com/watch?v=0zM3nApSvMg',
      'http://youtu.be/0zM3nApSvMg',
      '//www.youtube-nocookie.com/embed/up_lNV-yoK4?rel=0',
      'http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo',
      'http://www.youtube.com/watch?v=cKZDdG9FTKY&feature=channel',
      'http://www.youtube.com/watch?v=yZ-K7nCVnBI&playnext_from=TL&videos=osPknwzXEas&feature=sub',
      'http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I',
      'http://www.youtube.com/user/SilkRoadTheatre#p/a/u/2/6dwqZw0j_jY',
      'http://youtu.be/6dwqZw0j_jY',
      'http://www.youtube.com/watch?v=6dwqZw0j_jY&feature=youtu.be',
      'http://youtu.be/afa-5HQHiAs',
      'http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo?rel=0',
      'http://www.youtube.com/watch?v=cKZDdG9FTKY&feature=channel',
      'http://www.youtube.com/watch?v=yZ-K7nCVnBI&playnext_from=TL&videos=osPknwzXEas&feature=sub',
      'http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I',
      'http://www.youtube.com/embed/nas1rJpm7wY?rel=0',
      'http://www.youtube.com/watch?v=peFZbP64dsU',
      'http://youtube.com/v/dQw4w9WgXcQ?feature=youtube_gdata_player',
      'http://youtube.com/vi/dQw4w9WgXcQ?feature=youtube_gdata_player',
      'http://youtube.com/?v=dQw4w9WgXcQ&feature=youtube_gdata_player',
      'http://www.youtube.com/watch?v=dQw4w9WgXcQ&feature=youtube_gdata_player',
      'http://youtube.com/?vi=dQw4w9WgXcQ&feature=youtube_gdata_player',
      'http://youtube.com/watch?v=dQw4w9WgXcQ&feature=youtube_gdata_player',
      'http://youtube.com/watch?vi=dQw4w9WgXcQ&feature=youtube_gdata_player',
      'http://youtu.be/dQw4w9WgXcQ?feature=youtube_gdata_player'
  ];

  var failures = 0;
  urls.forEach(url => {
    const parsed = url.match(youtube_regex);
    if (parsed && parsed[2]) {
      console.log(parsed[2]);
    } else {
      failures++;
      console.error(url, parsed);
    }
  });
  if (failures) {
    console.error(failures, 'failed');
  }

实验版处理评论中提到的m.b utube网址:

const youtube_regex = /^.*((m\.)?youtu\.be\/|vi?\/|u\/\w\/|embed\/|\?vi?=|\&vi?=)([^#\&\?]*).*/

它需要在测试中的两个地方将已解析的[2]更改为已解析的[3](然后通过将m.u utube urls添加到测试中)。如果你发现问题请告诉我。

这里有一个红宝石版本:

def youtube_id(url)
   # Handles various YouTube URLs (youtube.com, youtube-nocookie.com, youtu.be), as well as embed links and urls with various parameters
   regex = /(?:youtube(?:-nocookie)?\.com\/(?:[^\/\n\s]+\/\S+\/|(?:v|vi|e(?:mbed)?)\/|\S*?[?&]v=|\S*?[?&]vi=)|youtu\.be\/)([a-zA-Z0-9_-]{11})/
   match = regex.match(url)
   if match && !match[1].nil?
      match[1]
   else
      nil
   end
end

测试方法:

example_urls = [
   'www.youtube-nocookie.com/embed/dQw4-9W_XcQ?rel=0',
   'http://www.youtube.com/user/Scobleizer#p/u/1/dQw4-9W_XcQ',
   'http://www.youtube.com/watch?v=dQw4-9W_XcQ&feature=channel',
   'http://www.youtube.com/watch?v=dQw4-9W_XcQ&playnext_from=TL&videos=osPknwzXEas&feature=sub',
   'http://www.youtube.com/ytscreeningroom?v=dQw4-9W_XcQ',
   'http://www.youtube.com/user/SilkRoadTheatre#p/a/u/2/dQw4-9W_XcQ',
   'http://youtu.be/dQw4-9W_XcQ',
   'http://www.youtube.com/watch?v=dQw4-9W_XcQ&feature=youtu.be',
   'http://youtu.be/dQw4-9W_XcQ',
   'http://www.youtube.com/user/Scobleizer#p/u/1/dQw4-9W_XcQ?rel=0',
   'http://www.youtube.com/watch?v=dQw4-9W_XcQ&playnext_from=TL&videos=dQw4-9W_XcQ&feature=sub',
   'http://www.youtube.com/ytscreeningroom?v=dQw4-9W_XcQ',
   'http://www.youtube.com/embed/dQw4-9W_XcQ?rel=0',
   'http://www.youtube.com/watch?v=dQw4-9W_XcQ',
   'http://youtube.com/v/dQw4-9W_XcQ?feature=youtube_gdata_player',
   'http://youtube.com/vi/dQw4-9W_XcQ?feature=youtube_gdata_player',
   'http://youtube.com/?v=dQw4-9W_XcQ&feature=youtube_gdata_player',
   'http://www.youtube.com/watch?v=dQw4-9W_XcQ&feature=youtube_gdata_player',
   'http://youtube.com/?vi=dQw4-9W_XcQ&feature=youtube_gdata_player',
   'http://youtube.com/watch?v=dQw4-9W_XcQ&feature=youtube_gdata_player',
   'http://youtube.com/watch?vi=dQw4-9W_XcQ&feature=youtube_gdata_player',
   'http://youtu.be/dQw4-9W_XcQ?feature=youtube_gdata_player'
]

# Test each one
example_urls.each do |url|
   raise 'Test failed!' unless youtube_id(url) == 'dQw4-9W_XcQ'
end

要查看此代码并在在线repl中运行测试，您也可以到这里: https://repl.it/@TomChapin/youtubeid

在c#中，它看起来是这样的:

public static string GetYouTubeId(string url) {
    var regex = @"(?:youtube\.com\/(?:[^\/]+\/.+\/|(?:v|e(?:mbed)?|watch)\/|.*[?&]v=)|youtu\.be\/)([^""&?\/ ]{11})";

    var match = Regex.Match(url, regex);

    if (match.Success)
    {
        return match.Groups[1].Value;
    }

    return url;
  }

请随意修改。

/^.*(youtu.be\/|v\/|e\/|u\/\w+\/|embed\/|v=)([^#\&\?]*).*/

测试:

http://www.youtube.com/v/0zM3nApSvMg?fs=1&hl=en_US&rel=0 http://www.youtube.com/embed/0zM3nApSvMg?rel=0 http://www.youtube.com/watch?v=0zM3nApSvMg&feature=feedrec_grec_index http://www.youtube.com/watch?v=0zM3nApSvMg http://youtu.be/0zM3nApSvMg http://www.youtube.com/watch?v=0zM3nApSvMg#t=0m10s http://www.youtube.com/user/IngridMichaelsonVEVO#p/a/u/1/KdwsulMb8EQ http://youtu.be/dQw4w9WgXcQ http://www.youtube.com/embed/dQw4w9WgXcQ http://www.youtube.com/v/dQw4w9WgXcQ http://www.youtube.com/e/dQw4w9WgXcQ http://www.youtube.com/watch?v=dQw4w9WgXcQ http://www.youtube.com/?v=dQw4w9WgXcQ http://www.youtube.com/watch?feature=player_embedded&v=dQw4w9WgXcQ http://www.youtube.com/?feature=player_embedded&v=dQw4w9WgXcQ http://www.youtube.com/user/IngridMichaelsonVEVO#p/u/11/KdwsulMb8EQ http://www.youtube-nocookie.com/v/6L3ZvIMwZFM?version=3&hl=en_US&rel=0

受到另一个答案的启发。

简单的正则表达式，如果你有完整的URL，保持简单。

results = url.match("v=([a-zA-Z0-9]+)&?")
videoId = results[1] // watch you need.