datetime.replace() is very slow when called with keyword arguments. For example, with python 3.13 from main on my laptop
$ python -m timeit -s "from datetime import datetime; dt = datetime.now()" "dt.replace(microsecond=0)"
500000 loops, best of 5: 501 nsec per loop
$ python -m timeit -s "from datetime import datetime" "datetime.now()"
2000000 loops, best of 5: 150 nsec per loop
$ python -m timeit -s "from datetime import datetime" "datetime(2020, 1, 1, 12, 34, 56, 123456)"
2000000 loops, best of 5: 119 nsec per loop
So calling replace() is over 4x slower than constructing a new datetime from components and over 3x slower than now(), which makes a system call.
Bug report
Bug description:
datetime.replace() is very slow when called with keyword arguments. For example, with python 3.13 from main on my laptop
For comparison,
So calling replace() is over 4x slower than constructing a new datetime from components and over 3x slower than now(), which makes a system call.
CPython versions tested on:
3.9, 3.10, 3.13
Operating systems tested on:
Linux
Linked PRs