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Python Python Collections (2016, retired 2019) Lists Disemvowel

Yang Bi
Yang Bi
10,079 Points

only removed half of the vowels..

ok. here is my script for this disemvowel question:

def disemvowel(word):

    word = list(word)

    for letter in word:

        if letter == 'a':

            word.remove('a')

        elif letter == 'e':

            word.remove('e')

        elif letter == 'i':

            word.remove('i')

        elif letter == 'o':

            word.remove('o')

        elif letter == 'u':

            word.remove('u')

        elif letter == 'A':

            word.remove('A')

        elif letter == 'E':

            word.remove('E')

        elif letter == 'I':

            word.remove('I')

        elif letter == 'O':

            word.remove('O')

        elif letter == 'U':

            word.remove('U')

    word = ''.join(word)

    return word  

print (disemvowel("aaaaaaeeeeeeiiiiiioooooouuuuuuf"))

running this script I can only remove half of the vowels. so my result is "aaaeeeiiiooouuuf" .

I don't know why this happened. is it because of the for loop is not looping every letter in my word? or my conditional if loop is skipping once every two vowels?

[MOD: added ```python formatting -cf]

2 Answers

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,423 Points

There are two issues:

  • the argument word is a string which does not have a remove() method. You will need to convert to a list first:

    word = list(word)
    

    Remember to convert the list back to a string using "".join(word)

  • As Steven mention, you shouldn't modify the iterable of a for loop. Use a copy instead:

    # use copy():
    for letter in word.copy():
    
    # use a slice (you will learn about this later in the Python course:
    for letter in word[:]:
    
Yang Bi
Yang Bi
10,079 Points

Thanks for the demo code. :)

Steven Parker
Steven Parker
229,708 Points

Never modify an iterable within the loop it is controllling, this can cause items to be skipped over.

Instead, iterate using a copy of the item, or construct a new item to return in the loop instead of modifying the original.

Steven Parker
Steven Parker
229,708 Points

I forgot to mention the point Chris pointed out about strings not having a remove method. But, if you wanted to use a slightly different strategy, they do have a replace method. :wink:

Yang Bi
Yang Bi
10,079 Points

Thank you Steven for your quick response.