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Python Regular Expressions in Python Introduction to Regular Expressions Word Length

João Robalo
João Robalo
1,028 Points

How to use se string format() on a raw string (r"foobar{var}".format(var)). Insert variable on raw string during regex.

I'm trying to complete this challenge:

"Create a function named find_words that takes a count and a string. Return a list of all of the words in the string that are count word characters long or longer."

The apparent solution is to return a re.findall() method with the raw string r"\w{count,}". The problem is getting that variable inside a raw string. The usual way I put variables inside a string is using the format method. So something like f"Hello, {name}" or "Hello, {0}".format(name).

However, this doesn't seem to work on a raw string and I need it to be a string in order to use the re.findall() method.

Here's what I tried

   def find_words(count, stringy):
          return re.findall(r"\w{{0},}".format(count), stringy)

This gives me the following error: Bummer: Single '}' encountered in format string

Thank you for your help.

word_length.py
import re

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

def find_words(count, stringy):
    return re.findall(r"\w{0,}".format(count), stringy)

1 Answer

Steven Parker
Steven Parker
210,867 Points

You were close! Each actual brace should be represented by two of the same together (and the 0 isn't needed):

    return re.findall(r"\w{{{},}}".format(count), stringy)