如何使用正则表达式在字符串中查找所有 YouTube 视频 ID？

Here's a method I once wrote for a project that extracts YouTube and Vimeo video keys:

/**
*  strip important information out of any video link
*
*  @param  string  link to a video on the hosters page
*  @return mixed  FALSE on failure, array on success
*/
function getHostInfo ($vid_link)
{
// YouTube get video id
if (strpos($vid_link, 'youtu'))
{
// Regular links
if (preg_match('/(?<=v\=)([\w\d-_]+)/', $vid_link, $matches))
return array('host_name' => 'youtube', 'original_key' => $matches[0]);
// Ajax hash tag links
else if (preg_match('§([\d\w-_]+)$§i', $vid_link, $matches))
return array('host_name' => 'youtube', 'original_key' => $matches[0]);
else
return FALSE;
}
// Vimeo get video id
elseif (strpos($vid_link, 'vimeo'))
{
if (preg_match('§(?<=/)([\d]+)§', $vid_link, $matches))
return array('host_name' => 'vimeo', 'original_key' => $matches[0]);
else
return FALSE;
}
else
return FALSE;
}

1. Find a regex that will extract all links from a text. Google will help you there.
2. Loop all the links and call getHostInfo() for each

Use:

<?php


// The YouTube URL string


$youtube_url='http://www.youtube.com/watch?v=8VtUYvwktFQ';


// Use regex to get the video ID


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


preg_match($regex, $youtube_url, $id);


// Plug that into our HTML
?>

Okay, I made a function of my own. But I believe it's pretty inefficient. Any improvements are welcome:

function get_youtube_videos($string) {


$ids = array();


// Find all URLs
preg_match_all('/(http|https)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/', $string, $links);


foreach ($links[0] as $link) {
if (preg_match('~youtube\.com~', $link)) {
if (preg_match('/[^=]+=([^?]+)/', $link, $id)) {
$ids[] = $id[1];
}
}
}
return $ids;
}

Try

[^\s]*youtube\.com[^\s]*?v=([-\w]+)[^\s]*

You will find the video IDs' in the first capturing group. What I don't know is what is a valid Video ID? At the moment I check for v= and capture all -A-Za-z0-9_.

I checked it online here on rubular with your sample string.

A YouTube video URL may be encountered in a variety of formats:

• latest short format: http://youtu.be/NLqAF9hrVbY
• iframe: http://www.youtube.com/embed/NLqAF9hrVbY
• iframe (secure): https://www.youtube.com/embed/NLqAF9hrVbY
• object param: http://www.youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US
• object embed: http://www.youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US
• watch: http://www.youtube.com/watch?v=NLqAF9hrVbY
• users: http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo
• ytscreeningroom: http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I
• any/thing/goes!: http://www.youtube.com/sandalsResorts#p/c/54B8C800269D7C1B/2/PPS-8DMrAn4
• any/subdomain/too: http://gdata.youtube.com/feeds/api/videos/NLqAF9hrVbY
• more params: http://www.youtube.com/watch?v=spDj54kf-vY&feature=g-vrec
• query may have dot: http://www.youtube.com/watch?v=spDj54kf-vY&feature=youtu.be
• nocookie domain: http://www.youtube-nocookie.com

Here is a PHP function with a commented regex that matches each of these URL forms and converts them to links (if they are not links already):

// Linkify youtube URLs which are not already links.
function linkifyYouTubeURLs($text) {
$text = preg_replace('~(?#!js YouTubeId Rev:20160125_1800)
# Match non-linked youtube URL in the wild. (Rev:20130823)
https?://          # Required scheme. Either http or https.
(?:[0-9A-Z-]+\.)?  # Optional subdomain.
(?:                # Group host alternatives.
youtu\.be/       # Either youtu.be,
| youtube          # or youtube.com or
(?:-nocookie)?   # youtube-nocookie.com
\.com            # followed by
\S*?             # Allow anything up to VIDEO_ID,
[^\w\s-]         # but char before ID is non-ID char.
)                  # End host alternatives.
([\w-]{11})        # $1: VIDEO_ID is exactly 11 chars.
(?=[^\w-]|$)       # Assert next char is non-ID or EOS.
(?!                # Assert URL is not pre-linked.
[?=&+%\w.-]*     # Allow URL (query) remainder.
(?:              # Group pre-linked alternatives.
[\'"][^<>]*>   # Either inside a start tag,
| </a>           # or inside <a> element text contents.
)                # End recognized pre-linked alts.
)                  # End negative lookahead assertion.
[?=&+%\w.-]*       # Consume any URL (query) remainder.
~ix', '<a href="http://www.youtube.com/watch?v=$1">YouTube link: $1</a>',
$text);
return $text;
}

; // End $YouTubeId.

And here is a JavaScript version with the exact same regex (with comments removed):

// Linkify youtube URLs which are not already links.
function linkifyYouTubeURLs(text) {
var re = /https?:\/\/(?:[0-9A-Z-]+\.)?(?:youtu\.be\/|youtube(?:-nocookie)?\.com\S*?[^\w\s-])([\w-]{11})(?=[^\w-]|$)(?![?=&+%\w.-]*(?:['"][^<>]*>|<\/a>))[?=&+%\w.-]*/ig;
return text.replace(re,
'<a href="http://www.youtube.com/watch?v=$1">YouTube link: $1</a>');
}

Notes:

• The VIDEO_ID portion of the URL is captured in the one and only capture group: $1.
• If you know that your text does not contain any pre-linked URLs, you can safely remove the negative lookahead assertion which tests for this condition (The assertion beginning with the comment: "Assert URL is not pre-linked.") This will speed up the regex somewhat.
• The replace string can be modified to suit. The one provided above simply creates a link to the generic "http://www.youtube.com/watch?v=VIDEO_ID" style URL and sets the link text to: "YouTube link: VIDEO_ID".

Edit 2011-07-05: Added - hyphen to ID char class

Edit 2011-07-17: Fixed regex to consume any remaining part (e.g. query) of URL following YouTube ID. Added 'i' ignore-case modifier. Renamed function to camelCase. Improved pre-linked lookahead test.

Edit 2011-07-27: Added new "user" and "ytscreeningroom" formats of YouTube URLs.

Edit 2011-08-02: Simplified/generalized to handle new "any/thing/goes" YouTube URLs.

Edit 2011-08-25: Several modifications:

• Added a Javascript version of: linkifyYouTubeURLs() function.
• Previous version had the scheme (HTTP protocol) part optional and thus would match invalid URLs. Made the scheme part required.
• Previous version used the \b word boundary anchor around the VIDEO_ID. However, this will not work if the VIDEO_ID begins or ends with a - dash. Fixed so that it handles this condition.
• Changed the VIDEO_ID expression so that it must be exactly 11 characters long.
• The previous version failed to exclude pre-linked URLs if they had a query string following the VIDEO_ID. Improved the negative lookahead assertion to fix this.
• Added + and % to character class matching query string.
• Changed PHP version regex delimiter from: % to a: ~.
• Added a "Notes" section with some handy notes.

Edit 2011-10-12: YouTube URL host part may now have any subdomain (not just www.).

Edit 2012-05-01: The consume URL section may now allow for '-'.

Edit 2013-08-23: Added additional format provided by @Mei. (The query part may have a . dot.

Edit 2013-11-30: Added additional format provided by @CRONUS: youtube-nocookie.com.

Edit 2016-01-25: Fixed regex to handle error case provided by CRONUS.

While ridgerunner's answer is the basis for my answer, his does NOT solve for all urls and I don't believe it is capable of it, due to multiple possible matches of VIDEO_ID in a YouTube URL. My regex includes his aggressive approach as a last resort, but attempts all common matchings first, vastly reducing the possibility of a wrong match later in the URL.

This regex:

/https?:\/\/(?:[0-9A-Z-]+\.)?(?:youtu\.be\/|youtube\.com(?:\/embed\/|\/v\/|\/watch\?v=|\/ytscreeningroom\?v=|\/feeds\/api\/videos\/|\/user\S*[^\w\-\s]|\S*[^\w\-\s]))([\w\-]{11})[?=&+%\w-]*/ig;

Handles all of the cases originally referenced in ridgerunners examples, plus any url that might happen to have an 11 character sequence later in the url. ie:

http://www.youtube.com/watch?v=GUEZCxBcM78&feature=pyv&feature=pyv&ad=10059374899&kw=%2Bwingsuit

Here is a working sample that tests all of the sample YouTube urls:

http://jsfiddle.net/DJSwc/5/

Find a YouTube link easily from a string:

function my_url_search($se_action_data)
{
$regex = '/https?\:\/\/[^\" ]+/i';
preg_match_all($regex, $se_action_data, $matches);
$get_url=array_reverse($matches[0]);
return array_unique($get_url);
}
echo my_url_search($se_action_data)

I tried a simple expression to get only the videoid:

[?&]v=([^&#]*)

Check it working online here at phpliveregex.

The original poster asked "I would like to parse it and find all YouTube video URLs and their ids." I switched the most popular answer above to a preg_match and returned the video id and URL.

Get YouTube URL and ID from post:

$match[0] = Full URL
$match[1] = video ID


function get_youtube_id($input) {
$input = preg_match('~https?://(?:[0-9A-Z-]+\.)?(?:youtu\.be/|youtube(?:-nocookie)?\.com\S*[^\w\s-])([\w-]{11})(?=[^\w-]|$)(?![?=&+%\w.-]*(?:[\'"][^<>]*>|</a>))[?=&+%\w.-]*~ix',
$input, $match);
return $match;
}

String urlid="" ;
String  url="http://www.youtube.com/watch?v=0zM4nApSvMg#t=0m10s";
Pattern pattern =Pattern.compile("(?:http|https|)(?::\\/\\/|)(?:www.|)(?:youtu\\.be\\/|youtube\\.com(?:\\/embed\\/|\\/v\\/|\\/watch\\?v=|\\/ytscreeningroom\\?v=|\\/feeds\\/api\\/videos\\/|\\/user\\\\S*[^\\w\\-\\s]|\\S*[^\\w\\-\\s]))([\\w\\-\\_]{11})[a-z0-9;:@#?&%=+\\/\\$_.-]*");
Matcher result = pattern.matcher(url);
if (result.find())
{
urlid=result.group(1);


}

This code in java works absolutely fine for all youtube urls at present.