CODEWITHSUNDEEP
pythonregex
Joel
Joel

Reputation: 59

How to match substring or whole string

In Python regex, how would I match only the facebook.com...777 substrings given either string? I don't want the ?sfnsn=mo at the end.
I have (?<=https://m\.)([^\s]+) to match everything after the https://m.. I also have (?=\?sfnsn) to match every thing in front of ?sfnsn.

How do I combine the regex to only return the facebook.com...777 part for either string.

have: https://m.facebook.com/story.php?story_fbid=123456789&id=7777777777?sfnsn=mo
want: facebook.com/story.php?story_fbid=123456789&id=7777777777

have: https://m.facebook.com/story.php?story_fbid=123456789&id=7777777777
want: facebook.com/story.php?story_fbid=123456789&id=7777777777

Here's what I was messing around with https://regex101.com/r/WYz5dn/2

(?<=https://m\.)([^\s]+)(?=\?sfnsn)

Upvotes: 0

Views: 310

Answers (2)

Rajat Jain
Rajat Jain

Reputation: 2022

Putting a ? at the end works, since the last grouped lookahead may or may not exist, we put a question mark after it:

(?<=https://m\.)([^\s]+)(?=\?sfnsn)?

Upvotes: -1

The fourth bird
The fourth bird

Reputation: 163207

You could use a capturing group instead of a positive lookbehind and match either ?sfnsn or the end of the string.

https://m\.(\S*?)(?:\?sfnsn|$)

Regex demo

Using the lookarounds, the pattern could be:

(?<=https://m\.)\S*?(?=\?sfnsn|$)

Regex demo

Upvotes: 2

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