CODEWITHSUNDEEP
pythonstringlist
pokemonfan
pokemonfan

Reputation: 207

Filtering objects from lists in python

I'm trying to program something that will filter all the vowels out of a string of text and I'm not sure why my function doesn't work. Here's my code

def anti_vowel(text):
 letters = text.split() #make a list of all the letters in the string
 index = 0 #for del
 for x in letters:
     if x == "a" or x == "A" or x == "u" or x == "U" or x == "i" or x == "I" or x == "o" or x == "O" or x == "e" or x == "E":
         del letters[index]
     index += 1 #to make the if-clause work
 return "".join(letters) #turn the edited list into a string

While iterating over letters the if-clause should be activated when the object in letters is a vowel right? so it should delete that object. But what am I doing wrong?

Upvotes: 1

Views: 202

Answers (5)

DJanssens
DJanssens

Reputation: 20859

You could use list comprehension and create something like this

def anti_vowel2(text):
    return "".join([x for x in text if x.lower() not in 'aeiou'])

print(anti_vowel2("test"))

which outputs the string tst

Upvotes: 1

Nir Alfasi
Nir Alfasi

Reputation: 53565

I rather Avinash's approach, but if you want to fix your impl. here's how to do it:

def anti_vowel(text):
    letters = list(text)
    i = 0
    while i < len(letters):
        x = letters[i]
        if x in "aAeEiIoOuU":
            del letters[i]
        else:
            i += 1
    return "".join(letters)

Upvotes: 2

Avinash Raj
Avinash Raj

Reputation: 174874

I would use re.sub

re.sub(r'(?i)[AEIOU]', '', st)

Explanation:

  • (?i) case-insensitive modifier helps to do case insensitive match.
  • [AEIOU] matches any one charcater from the given list. Since we already added the case-insensitive modifier, this would match both upper and lowercase vowels.

Upvotes: 5

TigerhawkT3
TigerhawkT3

Reputation: 49330

Your code isn't iterating through letters, it's iterating through words. This is because text.split() splits your text into a list of whitespace-separated "word" strings.

The next problem is that you're iterating through a list and deleting entries. Mutating an iterable while iterating through it is a common cause of strange results.

Instead, do something like this:

def anti_vowel(text):
    return ''.join(filter(lambda x: x.lower() not in 'aeioe', text))

Result:

>>> anti_vowel('hi my name is joe')
'h my nm s j'

Upvotes: 4

iobender
iobender

Reputation: 3496

''.join(c for c in text if c.lower() not in 'aeiou')

This uses a generator expression to look at each letter in the string, and only keep it if it is not a vowel (its lowercase is not in 'aeiou'), then joins these valid characters.

Upvotes: 1

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