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Python Regular Expressions in Python Introduction to Regular Expressions Negated Numbers

Jason Smith
Jason Smith
8,668 Points

Bummer: `good_numbers` seems to be missing or empty.

im not sure where i messed up, can you point me in the right direction?

negate.py
import re

string = '1234567890'

good_numbers = re.findall(r'[0-4][^5-7][8-9]', string)

3 Answers

Steven Parker
Steven Parker
228,991 Points

It looks like you got a bit overly-specific, and each of your character classes represent a different character.

A regex of '[0-4][^5-7][8-9]' will only match 3 consecutive characters where the first one is a digit between 0 and 4 (inclusive), the second one is anything other than 5, 6, or 7, and the last one is either 8 or 9. And of course, there are no instances like that in the test string.

Try making a bit simpler, specify only the requirements, and for a single character.

Steven Parker
Steven Parker
228,991 Points

The instructions say the "pattern matches anything in string except the numbers 5, 6, and 7.", so you really only want to use a single character class, and use it to only exclude those three digits. So you already have the right coding, but it's sandwiched between two other things you don't need.

Jason Smith
Jason Smith
8,668 Points

i was under the impression multiple sets meant multiple queries, can you give me an example of a similar one-set query?

Jason Smith
Jason Smith
8,668 Points

thanks for the hint! that was it