Match element then remove both elements

August 17, 2023

My list consists on several items:

["book","rule","eraser","clipboard","pencil",etc]

Let say I have an element ["book"] and I want to match with another element ["rule"] with the same len (4). then I want to remove both elements from the list.

["eraser","clipboard","pencil",etc]

I tried using a for loop and zip(lists, lists[1:]) but I can only remove the elements next to each other while other elements (like papers and pencil, len = 6) are never removed.

I want to remove same length words and have a final list with only the words whose length has no match or found no pair. For example:

["book","rule","eraser","clipboard","pencil","book"]

then the final list will be:

["clipboard","book"]

as book and clipboard found no pair.

>Solution :

You can try:

from collections import Counter

lst = ["book", "rule", "eraser", "clipboard", "pencil", "book"]

c = {k: v % 2 for k, v in Counter(map(len, lst)).items()}

out = []
for v in reversed(lst):
    if c[len(v)] == 1:
        out.append(v)
    c[len(v)] -= 1


print(out[::-1])

Prints: