regex_extract_id_from_link.py

'''
A simple regex approach to find specific portion (in this case post id) from a http link 
'''

import re

link = "https://www.facebook.com/marketplace/item/391273608941747/?ref=search&referral_code=undefined"
print(re.findall("marketplace/item/(\S*)/", str(link))[0])

# output
# 391273608941747