import timeit

print('starting...')
small = set(range(2000))
big = set(range(20000000))
difference = small - big

std_big = set(range(20))
std_small = set(range(2))

first = set(range(15))
second = set(range(22))

setup = """
gc.enable()
from __main__ import {a}, {b}
"""

fmt = """
a = {a}.copy()
b = {b}.copy()
a -= b
"""

fmt_subtraction = """
a = {a}.copy()
b = {b}.copy()
a - b
"""

print('setting up tests...', flush=True)

def timer(s, **vars):
    return timeit.Timer(s.format(**vars), setup.format(**vars))

bench = dict(
    big_timer = timer(fmt, a='small', b='big'),
    big_timer_no_intersection = timer(fmt, a='small', b='difference'),
    big_timer_reversed = timer(fmt, a='big', b='small'),
    big_timer_subtraction = timer(fmt_subtraction, a='small', b='big'),
    std_timer = timer(fmt, a='std_small', b='std_big'),
    std_timer_subtraction = timer(fmt_subtraction, a='std_small', b='std_big'),
    small_timer = timer(fmt, a='first', b='second'),
)


print('testing...', flush=True)
for name, test in bench.items():
    print(name, test.timeit(5), flush=True)