Test, validate and match regular expressions
Matches YouTube video URLs in multiple formats including standard watch links (youtube.com/watch?v=), shortened URLs (youtu.be/), embed paths, and /v/ URLs. Optionally accepts protocol (http/https) and www prefix, then captures the 11-character video ID (letters, digits, underscores, hyphens) for extraction. Also captures optional trailing query string parameters. Commonly used for validating user-submitted YouTube links or extracting video IDs from text.