python 查找列表中的重复元素

# 查找列表中的重复元素


def find_duplicate(arr):
    set_arr = set()
    dup = set()
    for x in arr:
        if x not in set_arr:
            set_arr.add(x)
        else:
            dup.add(x)
    return dup


if __name__ == '__main__':
    array = [1, 2, 3, 4, 4, 4, 4]
    print(find_duplicate(array))