List indexing is not that fast on Python 2 too: (py2) python -m perf timeit -s 's=[0]' 's[0]' Mean +- std dev: 31.7 ns +- 0.9 ns (py2) python -m perf tim

List indexing is not that fast on Python 2 too: (py2) python -m perf timeit -s 's=[0]' 's[0]' Mean +- std dev: 31.7 ns +- 0.9 ns (py2) python -m perf timeit -s 's={0:0}' 's[0]' Mean +- std dev: 44.5 ns +- 1.1 ns vs. Python 3: (py3.6) python -m perf timeit -s 's=[0]' 's[0]' Mean +- std dev: 36.7 ns +- 0.8 ns (py3.6) python -m perf timeit -s 's={0:0}' 's[0]' Mean +- std dev: 41.1 ns +- 1.0 ns