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Python Regular Expressions in Python Introduction to Regular Expressions Negated Numbers

keith rezendes
keith rezendes
4,459 Points
Posted by keith rezendes
keith rezendes
4,459 Points

What's up with the challenges lately, nothing seems to work and the error messages don't help.

See my code and more importantly, the error message, don't change string, I didn't even touch it.

negate.py 
import re

string = '1234567890'

good_numbers = re.findall(r'[^567]', string)

1 Answer

Tony Christopher
Tony Christopher
3,756 Points
Tony Christopher
Tony Christopher
3,756 Points

The problem is you're checking each character to see if it's a '5', '6' or '7' and then returning the character. If you run that in Python you'll see that the response is ['1', '2', '3', '4', '8', '9', '0'], which is not what is wanted. It should return ['1234', '890']. To get that you need to match groups of at least 1 character that isn't a '5', '6' or '7'. The correct solution is 

good_numbers = re.findall(r"[^567]+", string)