9. Non-unique Elements / Вирішуємо задачі на Python CheckIO Українською

# --------------------    tasks/non_unique.py ---------------

def checkio(data: list) -> list:

    res = []

    for i in data:
        if data.count(i) > 1:
            res.append(i)

    return res


def checkio_gen(data: list) -> list:
    return list(i for i in data if data.count(i) > 1)


def checkio_list_comp(data: list) -> list:
    return [i for i in data if data.count(i) > 1]


def checkio_filter(data: list) -> list:
    not_unique = lambda item: data.count(item) > 1
    return list(filter(not_unique, data))



# --------------   tests/test_non_unique.py   ------------------------


import pytest

from tasks.non_unique import checkio, checkio_gen, checkio_list_comp, checkio_filter


@pytest.mark.parametrize("func", [
    checkio, checkio_gen, checkio_list_comp, checkio_filter
])
@pytest.mark.parametrize(["collection", "res"], [
    [[1, 2, 3, 1, 3], [1, 3, 1, 3]],
    [[1, 2, 3, 4, 5], []],
    [[5, 5, 5, 5, 5], [5, 5, 5, 5, 5]],
    [[10, 9, 10, 10, 9, 8], [10, 9, 10, 10, 9]],
])
def test_non_unique(func, collection, res):
    assert func(collection) == res