to_datetime_vs_fromtimestamp.py

#!/usr/bin/python3

import numpy as np
from time import perf_counter
from pandas import to_datetime, Series

from datetime import datetime
fromtimestamp = datetime.fromtimestamp


rng = np.random.default_rng()
ints = Series(rng.integers(1, 1640084533, 200000))

slow_start = perf_counter()
slow = ints.apply(lambda ts: to_datetime(ts, unit="s"))
slow_stop = perf_counter()

fast_start = perf_counter()
fast = ints.apply(lambda ts: fromtimestamp(ts))
fast_stop = perf_counter()

print(f"Slow: {slow_stop-slow_start}\nFast: {fast_stop-fast_start}")

# Outcome;
# [mmazur@klapek ~]$ ./test.py
# Slow: 21.08506918803323
# Fast: 0.16851535497698933