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Python Python Collections (2016, retired 2019) Lists Disemvowel

Alejandro Byrne
Alejandro Byrne
2,562 Points
Posted by Alejandro Byrne
Alejandro Byrne
2,562 Points

Need answer with explanation.. been stuck on this challenge for a few days..

Ok, could someone please tell me how to solve this? I think I'm pretty close. sorry to bug you...

disemvowel.py 
def disemvowel(word):
    word = list(word)
    vowels = ['a', 'A', 'e', 'E', 'u', 'U', 'i', 'I', 'o', 'O']

    for item in word:
        if item in vowels:
            word.remove(item)
        else:
            continue


    return word
Alexander Davison
Alexander Davison
65,469 Points

Tagging Chris Freeman

3 Answers

Alexander Davison
Alexander Davison
65,469 Points 
def disemvowel(word):
    result = []
    for letter in word:
        if letter.lower() not in 'aeiou':
            result.append(letter)
    return ''.join(result)

Step-by-step Explanation:

  1. We define the function :laughing:
  2. We create an empty list containing no elements
  3. We go through every letter in the passed-in argument
  4. If the letter we're currently on lowercased isn't in 'aeiou'... (yes, you can check and see if a string is inside another string)
  5. (If the letter we are on isn't a vowel...) We add the letter to the reuslt list.
  6. Finally, we join together the list by using ''.join(result) and returning it. Think of ''.join(result) as result.join(''). It makes a little more sense that way, but remember that isn't valid Python!

I hope this helps :grin:

~Alex

Alejandro Byrne
Alejandro Byrne
2,562 Points
Alejandro Byrne
Alejandro Byrne
2,562 Points

Alright, thanks. It worked. Sorry for all the ruckus, I have to learn more about the .join method and checking wether a list/string is in another string/list.

slavster
slavster
1,551 Points
slavster
slavster
1,551 Points

Alexander Davison I really like your method of dealing with capitals. I was trying to write 2 For loops using the .lower() and .upper() function to handle both kinds. Your approach of looking at the word object, comparing all the letters in a single case, but then outputting the original case is much quicker. Very clever!

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

Never try to modify an item within a loop that is iterating that same item.

It will cause your loop to skip over some of the items. So instead, use a copy of the item to control the loop. An easy way to make a copy is using a slice with empty arguments.

Also, remember to convert your list back into a string before you return it!

Alejandro Byrne
Alejandro Byrne
2,562 Points
Alejandro Byrne
Alejandro Byrne
2,562 Points

How's this?

def disemvowel(word):
    word = []
    vowels = ['a', 'A', 'e', 'E', 'u', 'U', 'i', 'I', 'o', 'O']

    for item in word:
        if item in vowels:
            continue
        else:
            word.append(item)

    word = str(word)
    return word

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

Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

Exactly! By adding slice notations [:] a copy is made for the iterable which is then protected from changes to the actual value of word:

    for item in word[:]:
Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

Almost....

Applying my suggestions to your original code would give you this (and pass the challenge):

def disemvowel(word):
    word = list(word)
    vowels = ['a', 'A', 'e', 'E', 'u', 'U', 'i', 'I', 'o', 'O']

    for item in word[:]:  # loop using copy
        if item in vowels:
            word.remove(item)
        else:
            continue

    return ''.join(word)  # convert list back to string

But just for fun, Python also makes it possible to do essentially the same job in a single line:

def disemvowel(word):
    return ''.join([letter for letter in word if letter.lower() not in 'aeiou'])
Modou Sawo
Modou Sawo
13,141 Points
Modou Sawo
Modou Sawo
13,141 Points

Hi Alejandro,

1) Try putting your vowels variable outside the function.

2) Inside the function, assign an empty list to a variable (i.e. output) 3) Create a for loop, like so:

    for letter in list(word):
        if not letter.lower() in vowels:
            output += letter
    output = ''.join(output)
    return output

Like Steven said - you have to convert output list into a string.

Alejandro Byrne
Alejandro Byrne
2,562 Points
Alejandro Byrne
Alejandro Byrne
2,562 Points

Hmmmm... I'm sorry. I don't understand what to do, what changes do I make to the original function? I don't understand the code you gave me. Sorry for being so stubborn.