removing all duplicates except one

Question

I'm trying to remove all the duplicate words except for two certain words.

def reduceDuplicates(words, wordsIter):
    theWords=set()

    for word in words:

        if word!=FIRST or word!=LAST: #FIRST="first" #LAST="last"
            if word not in theWords:
                theWords.add(word)      #create new txt file 
        
        else:
            break

    words.__init__(theWords)     #call constructor to print

Does anybody know where to go with this? I've tried everything I can think of. The words "first" and "last" in my txt file keep losing their duplicates. I'm trying to keep those duplicates.

wordsIter is a list iterator that is supposed to handle mutator and accessor methods on the list of words variable

add sample input and expected output and also explain how actual output is different from the output you are expecting — deadshot, Apr 29 '22 at 18:33
Actually I'm trying to remove duplicates but not remove duplicates of a specific word. Could you help me? — John, Apr 29 '22 at 18:52
Why do you `break` when the `if` condition isn't satisfied? Any time `word==FIRST or word == LAST` your loop will break, so only the first instance of `FIRST` or `LAST` will ever be processed. Also you never add anything to your set in this situation. [How to debug small programs.](//ericlippert.com/2014/03/05/how-to-debug-small-programs/) | [What is a debugger and how can it help me diagnose problems?](//stackoverflow.com/q/25385173/843953) — Pranav Hosangadi, Apr 29 '22 at 19:03
Logically, `word!=FIRST or word!=LAST` is always true. See the linked duplicates. — kaya3, Apr 29 '22 at 19:44

physicalattraction · Accepted Answer · 2022-05-01T07:54:56.503

It is a bit unclear what words and wordsIter are in your code example. This function should do the trick though:

from typing import List, Set


def remove_duplicates(words: List[str], words_with_duplicates: Set[str]) -> List[str]:
    """
    Return the list of words in the same order, with all duplicates except those from `words_with_duplicates` removed
    """

    seen = set()
    return [x for x in words if x in words_with_duplicates or not (x in seen or seen.add(x))]


output = remove_duplicates(words=['A', 'B', 'C', 'B', 'D', 'D', 'C', 'B', 'D', 'B', 'A'],
                           words_with_duplicates={'B', 'D'})
assert output == ['A', 'B', 'C', 'B', 'D', 'D', 'B', 'D', 'B']

removing all duplicates except one

1 Answers1