Python script for removing words with certain letters in a list

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I am trying to run a simple python script that removes certain words containing certain letters originally part of a string, correctly separated into a list of words. I re-checked the code multiple times, yet the results are erroneous. What needs to be changed because I believe the code is correct. Please help.

s = """aline    amine
avine   azine
brine   chine
cline   coine
crine   daine
dwine   exine
ezine   faine
feine   foine
gwine   imine
koine   laine
Maine   opine
ovine   peine
quine   raine
rhine   saine
seine   shine
spine   swine
thine   trine
tsine   twine
Udine   urine
whine"""
words = list(s.split())
for i in words:
    if "s" in i:
        words.remove(i)
    elif "a" in i:
        words.remove(i)
    elif "d" in i:
        words.remove(i)
    elif "w" in i:
        words.remove(i)
    elif "u" in i:
        words.remove(i)

print(words)
list python string
3 Answers

In general, it's a bad idea to remove elements from a list as you're iterating over it, as the memory is shifting as you're trying to access it.

Instead, create a new list (using a list comprehension), only retaining the words which do not contain any of the forbidden letters (checking for whether a word contains a letter is done using in, and we generalize it to multiple letters using map()).

words = s.split()
result = [word for word in words if not any(map(lambda x: x in word, "adsuw"))]
user_177698150

You can also use the filter function which filters a list given a criterion.

def criterion(str_):
    # Returns True if str_ has none of the characters in list_
    # Returns False otherwise
    return all(c not in str_ for c in list_)

words = s.split()
list_ = ['s', 'a', 'd', 'w', 'u']
# also works: list_ = 'sadwu' 

result = list(filter(criterion, words))

or, in one line:

result = list(filter(lambda str_: all(c not in str_ for c in 'sadwu'), s.split()))
user_178974560

This would do the job, too:

words = s.split()
ex = ["s", "a", "d", "w", "u"]
words = [i for i in words if all(e not in i for e in ex)]
user_45168250
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