def has_dups(l):
    s = frozenset(l)
    return len(s) < len(l)

def has_dups_list(l):
    for v in l:
        count = 0
        for v2 in l:
            if v == v2:
                count += 1
                if count > 1:
                    return True
    return False

def timing(func, argument, repeat=100):
    import time
    total = 0.0
    for i in range(repeat):
        start = time.time()
        func(argument)
        total += time.time() - start
    print("Average time (ms):", total / repeat * 1000.0)

def check(test_list):
    print(has_dups(test_list), has_dups_list(test_list))
    timing(has_dups, test_list)
    timing(has_dups_list, test_list)

test_list = list(range(1000))
check(test_list)
test_list = list(range(1000)) ; test_list[-1] = test_list[500]
check(test_list)
test_list = list(range(1000)) ; test_list[1] = test_list[0]
check(test_list)