I have a url pattern that takes the following form:

1. https://www.facebook.com/foo123/photos/1234/
2. https://www.facebook.com/foo123/photos/a.123/1234/

In this case I need to extract string after /photos/

eg:

1. In case 1 the valid string is 1234
2. in case 2 the valid string is 1234

I drafted the the following regex but it fails on case 2

\/photos\/([^\/\?] )

so essentially grabbing everything after /photos/ followed by / ?

I need a simple regex that can also work in case 2

so the logic is:

the string is either found after /photos/ or one level after /photos/. The string only contains digits. If the string if found after /photos/ it would end with /. if it is found one level after /photos/ it would also end with /

CodePudding user response：

You can extract the digit chunk after any chars other than /, ? and digits:

\/photos\/(?:.*?\/)?(\d )(?![^\/])

See the regex demo.

Details:

• \/photos\/ - a /photos/ string
• (?:.*?\/)? - an optional sequence of any zero or more chars as few as possible and then a / char
• (\d ) - Group 1: one or more digits
• (?![^\/]) - end of string or /.