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Python Regular Expressions in Python Introduction to Regular Expressions Word Length

How to put a variable into the {} with re

So if I have {count} my code does not work... but if I take it into another interpreter I can see it does work when I have a value e.g. {4}

How come I pass the count variable into this {} ?

import re

# >>> find_words(4, "dog, cat, baby, balloon, me")
# ['baby', 'balloon']
def find_words(my_count, my_string):
  return re.findall(r'\w{my_count}', my_string) 

2 Answers

There's a more concise and consequently more opaque alternative to .format that does work here: return re.findall(r'\w{%d,}' % my_count, my_string)

There's a manageable tutorial here. I didn't think the Python documentation was very clear on this one.

Chase Marchione
Chase Marchione
155,055 Points

Hi David,

You'll want to explicitly convert my_count to a string, and place it outside of the quotes (when it's within quotes, the compiler interprets it as literal characters rather than a variable).

return re.findall(r'\w{' + str(my_count) + ',}', my_string)

Hope this helps!

Ahhh, I had tried a conversion- but to int I tried !!

It does work CJ Marchione- but I don't think that is the only way this can be done, it is way too hacky to be the desired approach !!