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Python Regular Expressions in Python Introduction to Regular Expressions Word Length

David Hortensius
David Hortensius
3,898 Points
Posted by David Hortensius
David Hortensius
3,898 Points

Creating a concatenated string for the regex input

Hello,

I'm trying to get my fingers around the word_length challenge and came up with the idea to make a string of my regex 'input', also thanks to this forum posts.

  reg_string = "r'\w{" + str(count) + ",}'"
  return re.findall(reg_string, string)

But that doesn't work. If I check the forum I see:

  reg_string = r'\w{' + str(count) + ',}'

And that works perfectly well. Though, I don't understand. Why do I on one instance need quotes at the beginning and end to concatenate a string variable and in this case using none is perfectly fine?

Hope you can help me with that.

1 Answer

jacinator
jacinator
11,936 Points

I think that it's because in your example the r is inside the opening quote. The would mean that it's not a regular expression. The copy of code that you got from the forum is a regular expression because the r is outside the opening quote.