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Python Regular Expressions in Python Introduction to Regular Expressions Word Length

Why this isn't working?

print(re.findall(r'\b\w{3}+\b', "dog, cat, baby, balloon, me")) if I do this, it gives me the correct answer but when I put this concept in function, it gives me emplty list.

import re

# >>> find_words(4, "dog, cat, baby, balloon, me")
# ['baby', 'balloon']
def find_words(count, data):
    return re.findall(r'\b\{count}+\b', data)

2 Answers

You have a literal string in your regular expression, so count is taken literally, not as a variable.

This was actually quite tricky to fix, because of the weird ways string interpolation works in python.

def find_words(count, data):
  pattern = r'\b\w{%s}\b' %(count)
  return re.findall(pattern, data)

thank you.