Remove words from a list that end with a suffix without using endswith()

Question

I want to write a python function that takes 2 parameters:

List of words and
Ending letters

I want my function to work in such a way that it modifies the original list of words and removes the words which end with the "ending letters" specified.

For example:

list_words = ["hello", "jello","whatsup","right", "cello", "estello"]
ending = "ello"

my_func(list_words, ending)

This should give the following output:

list_words = ["whatsup","right"]

It should pop off all the strings that end with the ending letters given in the second argument of the function.

I can code this function using the .endswith method but I am not allowed to use it. How else can I do this using a loop?

`string.endswith('ello')` is equivalent to `string[-4:] == 'ello'`. — Matthias Fripp, Oct 02 '21 at 19:06
Not being allowed to use the standard library sounds like an exercise in using other mechanisms. Here's a starting point: can you access parts of a string? — Yann Vernier, Oct 02 '21 at 19:07
You can use `word[-len(ending):] == ending` insted of `word.endswith(ending)` — Anwarvic, Oct 02 '21 at 19:07
Programming is all about decomposition: breaking large problems into small pieces. Can you write your own `endswith` function that checks if a string has a particular suffix and returns `True` or `False`? Once you write that then you can tackle the whole list removal deal. — John Kugelman, Oct 02 '21 at 19:07

Gabio · Accepted Answer · 2021-10-02T20:04:10.403

3

Try:

def my_func(list_words, ending):
    return [word for word in list_words if word[len(word)-len(ending):] != ending]

edited Oct 02 '21 at 20:04

answered Oct 02 '21 at 19:10

Gabio

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X should be word right – Sangeerththan Balachandran Oct 02 '21 at 19:55

Gangula · Answer 2 · 2021-10-02T20:56:37.360

0

You can easily check for the last4 characters of a string using string[-4:].

So you can use the below code

list_words = ["hello", "jello","whatsup","right", "cello", "estello"]
ending = "ello"

def my_func(wordsArray, endingStr):
    endLen = len(endingStr)
    output = []
    for x in wordsArray:
        if not x[-endLen:] == endingStr:
            output.append(x)
    return output

list_words = my_func(list_words, ending)

You can shorten the function with some list comprehension like this:

def short_func(wordsArray, endingStr):
    endLen = len(endingStr)
    output = [x for x in wordsArray if x[-endLen:] != endingStr]
    return output

list_words = short_func(list_words, ending)

edited Oct 02 '21 at 20:56

answered Oct 02 '21 at 19:10

Gangula

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But the length of the ending characters depends on the parameter ending, I need something not specific to the ending "ello". For eg, my code should also work if the ending is set to be say, "tion" or "ate". – yowhatsup123 Oct 02 '21 at 19:13
right, then its easy to calculate the `len(ending`) and use that instead of `-4`. I updated the answer to support this – Gangula Oct 02 '21 at 19:14
`NameError: name 'endLen' is not defined` – no comment Oct 02 '21 at 19:24
1

It should be inside the function check my answer – Sangeerththan Balachandran Oct 02 '21 at 19:25
2

@SangeerththanBalachandran And now you guys just need to fix the more subtle bug :-P (you don't handle all possible `ending` strings correctly). – no comment Oct 02 '21 at 19:29
@Gangula I have to modify the current list and not make a new one – yowhatsup123 Oct 02 '21 at 20:41
1

@SangeerththanBalachandran I meant `ending = ''`. – no comment Oct 02 '21 at 20:42
It will also be handled if we check the len(word) > len(ending) – Sangeerththan Balachandran Oct 02 '21 at 20:45
1

@SangeerththanBalachandran Was that supposed to be a reply to me? – no comment Oct 02 '21 at 20:53
@yowhatsup123, if you need to modify existing list, you can just re-assign the variable to the output of the function. Updated the answer accordingly. – Gangula Oct 02 '21 at 20:54
@don't talk just code yeah – Sangeerththan Balachandran Oct 02 '21 at 20:57
Also, I think the rest of simple tweaks that you're looking for are pretty straight forward. Try to take some time, you'll definetely find an answer before looking for suggestions. This will help you in the long run – Gangula Oct 02 '21 at 20:58
@SangeerththanBalachandran I changed your code to use `>`, but as expected, that didn't fix it. – no comment Oct 02 '21 at 20:58
@don'ttalkjustcode what is the issue – Sangeerththan Balachandran Oct 02 '21 at 21:00
@SangeerththanBalachandran The wrong result. – no comment Oct 02 '21 at 21:03
I have edited it did you checked – Sangeerththan Balachandran Oct 02 '21 at 21:07
@SangeerththanBalachandran You keep forgetting to address/notify me. You mean yours? It's still `>=` instead of `>`, and both versions get it wrong. – no comment Oct 02 '21 at 21:14
@don't talkjustcode can you share the test cases. Probably we can have a chat later. – Sangeerththan Balachandran Oct 02 '21 at 21:18
@SangeerththanBalachandran I already did, and I know you saw it because you replied to it. – no comment Oct 02 '21 at 21:21
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/237732/discussion-between-sangeerththan-balachandran-and-dont-talk-just-code). – Sangeerththan Balachandran Oct 02 '21 at 21:24

Sangeerththan Balachandran · Answer 3 · 2021-10-02T21:35:14.717

0

It is always better to not modify the existing list you can get a list which doesn't have the words with the ending specified like below. If you want to have it as a function you can have it in a following manner. You can assign the formatted list to list_words again.

def format_list(words, ending):
    new_list = []
    n = len(ending)
    for word in words:
        if len(word) >= n and  n > 0:
            if not word[-n:] == ending:
                new_list.append(word)
        else:
            new_list.append(word)
    return new_list 

list_words = format_list(list_words, ending)
print(list_words)

edited Oct 02 '21 at 21:35

answered Oct 02 '21 at 19:15

Sangeerththan Balachandran

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This question clearly states that I am supposed to modify the list using .pop and not create a new list – yowhatsup123 Oct 02 '21 at 20:22
list_words = format_list(list_words, ending) print(list_words) – Sangeerththan Balachandran Oct 02 '21 at 20:36
Is this the one you are expecting – Sangeerththan Balachandran Oct 02 '21 at 20:38
1

Never mind, this worked, thanks alot!!! – yowhatsup123 Oct 02 '21 at 20:52

score 0 · Answer 4 · answered Oct 02 '21 at 19:15

0

def filter_words(list_words, ending):
    return [*filter(lambda x: x[-len(ending):] != ending , list_words)]

answered Oct 02 '21 at 19:15

zyrafal

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no comment · Answer 5 · 2021-10-02T20:45:09.400

0

Not allowed to use endswith? Not a problem :-P

def my_func(list_words, ending):
    list_words[:] = [word for word in list_words
                     if not word[::-1].startswith(ending[::-1])]
    return list_words

Loopholes ftw.

(Adapted to your insistence on modifying the given list. You should probably really decide whether to modify or return, though, not do both, which is rather unusual in Python.)

edited Oct 02 '21 at 20:45

answered Oct 02 '21 at 19:32

no comment

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Remove words from a list that end with a suffix without using endswith()

5 Answers5