Regex for parsing subreddit, IDs, and URL params out of a Reddit URL. Battle-hardened and tested for over three years on Reddit bots GifReversingBot, vredditshare, and switcharoohelper.
Returns the following information if it is exists in a Reddit URL
/r/ or /user/ depending on whether this is in a sub or a user page
subreddit name
/comments/ if this is a comments page (mostly useless, just needed to do subsequent captures)
Submission ID
Comment ID
? if there are URL parameters
URL Parameters (you'll need to parse them through something else to get keys and values)