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Python Regular Expressions in Python Introduction to Regular Expressions Groups

Posted by Adiv Abramson
Adiv Abramson
6,919 Points

Since \w includes \d, why are both included in the character class r'[-\w\d]' ?

In this case, wouldn't the specification \w\d be redundant? I have read that with RegEx you want to avoid placing tokens together where a given token's match could possibly be included in the previous token's match. I probably don't quite understand the concept. Can you clarify? Thank you

Y B
Y B
14,136 Points
Y B
Y B
14,136 Points

I would love to know this aswell. After working through the course the impression i got was they were separate and was surprised when using a \w expression in the interpreter that it picked up numbers too.

1 Answer

Kenneth Love
STAFF
Kenneth Love
Treehouse Guest Teacher
Kenneth Love
Kenneth Love
Treehouse Guest Teacher

I suppose, if you were really, really concerned about performance, you'd just use \w if you wanted both characters. You'd, of course, use \d if you only wanted numbers. Like most performance things, though, it's going to be an issue only for an extreme minority.