non-unique-elements.py

# Your optional code here
# You can import some modules or create additional functions


def checkio(data):
    # Your code here
    # It's main function. Don't remove this function
    # It's used for auto-testing and must return a result for check.

    # replace this for solution

    data_count = {}

    for d in data:
        count = data_count.get(d, 0)
        data_count[d] = count + 1

    unique = [k for k, v in data_count.items() if v <= 1]
    return [d for d in data if d not in unique]


# Some hints
# You can use list.count(element) method for counting.
# Create new list with non-unique elements
# Loop over original list


if __name__ == "__main__":
    # These "asserts" using only for self-checking and not necessary for auto-testing
    assert isinstance(checkio([1]), list), "The result must be a list"
    assert checkio([1, 2, 3, 1, 3]) == [1, 3, 1, 3], "1st example"
    assert checkio([1, 2, 3, 4, 5]) == [], "2nd example"
    assert checkio([5, 5, 5, 5, 5]) == [5, 5, 5, 5, 5], "3rd example"
    assert checkio([10, 9, 10, 10, 9, 8]) == [10, 9, 10, 10, 9], "4th example"