在多个列表中查找重复项并返回 Python 中每个列表的重复项计数

Question

There are multiple lists,

[1,2], [2,3,4], [3,4,5], [6,8,9,10]...

Is there a way to find and count duplicates for each list? so for lists above, I want to get:

[1,2] --- 1 duplicate which is 2

[2,3,4] --- 3 duplicates which are 2,3,4

[3,4,5] --- 2 duplicates which are 3, 4

[6,7,8,9] - 0 duplicate

I am thinking that I can find the duplicates, then compare each list against duplicates and get the results.

Is there a better/faster way to do it? Thanks for any suggestions.

Answer 1

Sure, there's a way to do this.

First, put your lists into a list.

list_of_lists = [[1,2], [2,3,4], [3,4,5], [6,8,9,10]]

Then, figure out all the items you have:

all_items = [n for l in list_of_lists for n in l]

Then figure out which items are duplicated:

duplicates = set([n for n in all_items if all_items.count(n) > 1])

Then calculate duplicates for each list:

for l in list_of_lists:
    duplicate_count = len([n for n in l if n in duplicates])
    print("Duplicates: ", duplicate_count)

Incidentally, I think you want 3 for the second answer, since both 2, 3, and 4 are all duplicated in your lists.

Duplicates:  1
Duplicates:  3
Duplicates:  2
Duplicates:  0