I found this "[\\?&]v=([^&#]*)" on the internet can someone explain it to me
javascript, parsing, regex, youtube
Solution
It's using a regular expression to extract the ID of the video from a complete URL. This particular regex breaks down as follows:
- `[\\?&]` is a character class. It matches a single character which is either `&` or `?`. (The question mark is a special character in JavaScript regexes, so it must be escaped by preceding it with a backslash. The backslash is a special character in JavaScript strings, so it must be escaped also, hence the double backslash. That's fairly common in regular expressions.)
- `v=` matches the literal string `v=`.
- `(` begins a capturing group, so everything until the next `)` will be placed into a separate entry in the returned array.
- `[^&#]*` any number of characters (including none) until a `&` or `#` is found. The brackets indicate a character class as above, and the `^` inverts the class so it includes all characters except those listed before the end bracket. The `*` indicates that the preceding character class is to be matched zero or more times.
- The `)` ends the capturing group.
Assuming the match is successful, `results[0]` contains the entire URL, and `results[1]` contains the contents of the first capturing group, i.e. the ID of the video.
Problem
I found a method on the internet that can retrieve the Id of a youtube video from the url. this is it. ``` var vid; var results; results = url.match("[\\?&]v=([^&#]*)"); vid = ( results === null ) ? url : results[1]; ``` The Id will be contained in "vid". What I don't understand and I find interesting and want to know is this. ``` results = url.match("[\\?&]v=([^&#]*)"); ``` How does it work?