用于匹配子字符串的可选非捕获组

Question

Given the following example strings

//www.youtube.com/embed/OYb_N_XEYas?rel=0&showinfo=0
//www.youtube.com/embed/STH9ZpeFH2o

I need to capture the sub-string after 'embed/' up to either the end of the string or either a '?' or '/' character.

How do I specify the optional second non-capturing group?

using (embed\/)(.*) works for the second string, and (embed\/)(.*)(\?|\/) works for the first, but neither works in both cases.

Answer 1

You could use this regex:

embed\/([^?\/]*)

In short it'll match all characters that aren't ? or /, and put them in group 1. Thus it'll work regardless of the presence of such characters, i.e. it'll work for both sample strings.

Note that this will catch an empty string, just substitute + for * if you don't want it to.

I also removed the group around embed\/ as I saw no reason to have it.