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Python Python Collections (2016, retired 2019) Lists Disemvowel

Posted by Ethan Haezebroeck
Ethan Haezebroeck
16,767 Points

When I use the remove function for this, the letter gets removed but it skips a letter as the indexes shift in the list.

How do I prevent this from happening

disemvowel.py 
def disemvowel(word):
    words = list(word)
    vowels = ['a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U']
    for letter in words:
        for vowel in vowels:
            if vowel == letter:
                words.remove(vowel)
    word = "".join(words)
    return word

1 Answer

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

You've discovered the reason why modifying an interable inside the loop that is using it is a bad idea!

Two ways around this are:

  • iterating with a copy of the iterable (easily made with a slice)
  • creating a new list in the loop and returning that instead