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Python Regular Expressions in Python Introduction to Regular Expressions Negated Numbers

Mar Bocatcat
Mar Bocatcat
7,405 Points


What am i missing here? Any advice?

import re

string = '1234567890'

def good_numbers(string):
  return re.findall(r'[\w\d][^567]', string, re.I)

1 Answer

Chris Freeman
Chris Freeman
Treehouse Moderator 67,736 Points

Hi Mar,

There are two issues with your solution. First, the task asks only to create a variable named good_numbers, not a function.

Second, your regex is overly complicated for the task. By combining two character sets your regex r'[\w\d][^567]' says:

`[any word or decimal character][not followed by 5 6 or 7]' this means the "7" will still be found "good" because it is follow by "8".

Your regex need only say `[not a 5, 6 or 7]'. This can be accomplished using:

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

The re.I is not needed since there is no character case to ignore.

Best of luck. Keep Coding!

Mar Bocatcat
Mar Bocatcat
7,405 Points

Thank you ! I need to read the details more!