Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Regular Expressions in Python Introduction to Regular Expressions Word Length

Posted by Tan Yang
Tan Yang
13,163 Points

regext: r"\w{count,}"

I set regex r"\w{count}", count is an integer variable, but it does't return correct result. How can I pass a variable to regex format

word_length.py 
import re

# EXAMPLE:
# >>> find_words(4, "dog, cat, baby, balloon, me")
# ['baby', 'balloon']

def find_words(count, string):
    lst = re.findall(r"\w{count,}", string)
    return lst

1 Answer

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

Python won't interpolate in a raw "r" string, for that you need an "f" string. But then you'll also need to put braces around the variable name and double the braces that you want to keep (as braces):

    lst = re.findall(f"\w{{{count},}}", string)