PHP preg_match模式 - 小问题

Question

I need a pattern which matches

youtube.com/watch?v=iNAMI8DQc8M

and

youtu.be/iNAMI8DQc8M

it should return the video id, in this case iNAMI8DQc8M

I tried this pattern:

youtu[.*][be|be\.com]\/+(.+)

but that does not work, I am not really good with regex.

Answer 1

$str = 'youtube.com/watch?v=iNAMI8DQc8M';
$id = get_id($str);

function get_id($str) {
    $matches = array();

    if (preg_match('/youtu\.?be\/?(\.com\/watch\?v=)?([\w]+)/', $str, $matches)) {
        $id = $matches[2];
    }
    return $id;
}

It's extremely tolerant, but it works.

We know youtu will be there no matter what, so there it is. youtu

The first part checks for a . before be. It could be there, but doesn't need to be there. \.?be

There is a check for the .com/watch?v= part, too, which is also unnecessary, but okay to have. (\.com\/watch\?v=)?

After that, we match the video ID. ([\w]+)