Attempting to return indices of vowels in a string

Question

For this code I pretty much have it so that it will return certain indices, but it counts multiple vowels in the same index. I just realized that index() only returns the first occurrence of the item, but now I've pretty much exhausted other possibilities.

def vowel_indices(s):
'string ==> list(int), return the list of indices of the vowels in s'
res = []
for vowel in s:
    if vowel in 'aeiouAEIOU':
        res = res + [s.index(vowel)]
return res

An example of this working is:

vowel_indices('hello world')

[1, 4, 7]

Instead I end up getting [1,4,4] as the return.

Jon Clements · Accepted Answer · 2013-02-04T00:17:05.637

4

Use a list comp with enumerate:

vowel_indices = [idx for idx, ch in enumerate(your_string) if ch.lower() in 'aeiou']

edited Feb 04 '13 at 00:17

answered Feb 04 '13 at 00:12

Jon Clements

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Alright, thank you! This works perfectly now. – iKyriaki Feb 04 '13 at 00:18
You might want to apply [this](http://stackoverflow.com/q/517923/674039) before checking in `'aeiou'` – wim Feb 04 '13 at 00:23

score 1 · Answer 2 · answered Feb 04 '13 at 00:16

Your problem is that .index() stops at the first occurrence of your vowel, so duplicate vowels that come later don't get noticed.

Instead of using .index(), use a counter variable (sort of like a C++ for loop):

def vowel_indices(s):
    res = []
    index = 0

    for vowel in s:
        index += 1

        if vowel.lower() in 'aeiou':
            res.append(index)

    return res

Or use enumerate():

def vowel_indices(s):
    res = []

    for index, vowel in enumerate(s):
        if vowel.lower() in 'aeiou':
            res.append(index)

    return res

Attempting to return indices of vowels in a string

2 Answers2