Double letter matching using python regex

Question

I am trying to find a way using regex to match words that have 3 unique sets of double letters. so far i have this:

r".*([a-z])\1.*([a-z])\2.*([a-z])\3.*"    

But that doesn't account for unique sets for double letters. Thanks in advance =)

Answer 1

Maybe like this? Seems to work for me.

r".*([a-z])\1.*((?=(?!\1))[a-z])\2.*((?=(?!\1))(?=(?!\2))[a-z])\3.*"

(?=expr) is a non-consuming regular expression, and (?!expr) is regex NOT operator.