set_vs_list_membership_testing.py

# note, using the %%timeit ipython magic, the expression on the first line is not included in the time testing

In [3]: %%timeit items = list(map(str, range(1)))
   ...: 'foo' in items
   ...:
   ...:
33 ns ± 1.79 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

In [4]: %%timeit items = set(map(str, range(1)))
   ...: 'foo' in items
   ...:
   ...:
25.5 ns ± 0.395 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

In [5]: %%timeit items = list(map(str, range(100)))
   ...: 'foo' in items
   ...:
   ...:
993 ns ± 9 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

In [6]: %%timeit items = set(map(str, range(100)))
   ...: 'foo' in items
   ...:
   ...:
26.2 ns ± 0.645 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

In [7]: %%timeit items = list(map(str, range(1000)))
   ...: 'foo' in items
   ...:
   ...:
12.6 µs ± 77.9 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

In [8]: %%timeit items = set(map(str, range(1000)))
   ...: 'foo' in items
   ...:
   ...:
29.3 ns ± 0.47 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)