#36215: Use PEP 448 unpacking to concatenate iterables
-------------------------------------+-------------------------------------
Reporter: Aarni Koskela | Owner: (none)
Type: | Status: new
Cleanup/optimization |
Component: Uncategorized | Version: 5.1
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Aarni Koskela):
Ah, sorry, yeah, I left the microbenchmarks out of the original ticket
text for brevity.
{{{
BLANK_CHOICE_DASH = [("", "---------")]
def get_action_choices_1(default_choices=BLANK_CHOICE_DASH):
choices = [] + default_choices
...
return choices
def get_action_choices_2(default_choices=BLANK_CHOICE_DASH):
choices = [*default_choices]
...
return choices
}}}
(adapted from what `get_action_choices` in the admin does)
results in
{{{
$ uv run --python=3.13 concates.py
name='get_action_choices_1' iters=5000000 time=0.247
iters_per_sec=20206826.98
name='get_action_choices_2' iters=5000000 time=0.207
iters_per_sec=24111147.61
$ uv run --python=3.12 concates.py
name='get_action_choices_1' iters=5000000 time=0.333
iters_per_sec=15023921.85
name='get_action_choices_2' iters=5000000 time=0.220
iters_per_sec=22699169.61
}}}
However, now that I benchmark some other expressions (such as some tuple
concatenations), they may actually be slower in some of these cases; it
looks like CPython internally converts the first input tuple to a list
(`BUILD_LIST`), then calls an `INTRINSIC_LIST_TO_TUPLE` opcode on it...
--
Ticket URL: <https://code.djangoproject.com/ticket/36215#comment:2>
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