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Python Python Collections (2016, retired 2019) Lists Disemvowel

Yang Bi
Yang Bi
10,079 Points
Posted by 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 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 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
Yang Bi
Yang Bi
10,079 Points

Thanks for the demo code. :)

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 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
231,269 Points
Steven Parker
Steven Parker
231,269 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
Yang Bi
Yang Bi
10,079 Points

Thank you Steven for your quick response.