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Python Regular Expressions in Python Introduction to Regular Expressions Word Length

Jason Smith
Jason Smith
8,361 Points
Posted by Jason Smith
Jason Smith
8,361 Points

bummer: 'NoneType' object not iterable

i tried to put everything on one line, what mistake did i make?

word_length.py 
import re

def find_words(count, string):
    return(list(re.search(r'\w{count,}', string)))
# EXAMPLE:
# >>> find_words(4, "dog, cat, baby, balloon, me")
# ['baby', 'balloon']

2 Answers

Steven Parker
Steven Parker
221,070 Points
Steven Parker
Steven Parker
221,070 Points

Part of the issue is that you don't want the literal word "count" in your RegEx expression.

Instead, use a mechanism like concatenation, the "format" function, or an "f-string" to include the value of the "count" variable (as a string) in the expression.

Also, "search" will only give the first match. To get them all, use "findall" instead — and you won't need "list".

Steven Parker
Steven Parker
221,070 Points
Steven Parker
Steven Parker
221,070 Points

The "f-string" is a relatively new feature in Python that does token substitution in a string without needing the "format" method. For example:

print("My name is {}.".format(name))  # format method
print(f"My name is {name}.")          # f-string method

It's a bit tricky to use f-strings with regex, but it's possible with proper escaping.

Happy coding!

Jason Smith
Jason Smith
8,361 Points
Jason Smith
Jason Smith
8,361 Points

what's an f-string?