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GeezerVison is showing github.com — gh-142863: optimize list and set calls with generator expressions by kumaraditya303 · Pull Request #142864 · python/cpython

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@kumaraditya303

@kumaraditya303 kumaraditya303 commented Dec 17, 2025 •
edited by bedevere-app Bot
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  • Issue: optimize list/set calls with generator expression #142863

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kumaraditya303 added 3 commits December 17, 2025 14:13
@kumaraditya303
optimize for list
3b04c79
@kumaraditya303
optimize for sets
99fb67b
@kumaraditya303
add comment
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@bedevere-app bedevere-app Bot mentioned this pull request Dec 17, 2025
optimize list/set calls with generator expression #142863
Closed
kumaraditya303 and others added 3 commits December 17, 2025 15:15
@kumaraditya303
fix test_dis
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@kumaraditya303
Merge branch 'main' into optimize-list-set
6870f1c
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📜🤖 Added by blurb_it.
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@kumaraditya303
kumaraditya303 marked this pull request as ready for review December 17, 2025 10:37
@kumaraditya303
kumaraditya303 requested review from ZeroIntensity, ericsnowcurrently, iritkatriel and markshannon as code owners December 17, 2025 10:37
@bedevere-app bedevere-app Bot added the awaiting core review label Dec 17, 2025
@kumaraditya303

kumaraditya303 commented Dec 23, 2025

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Benchmark results:

Before:

❯ ./python.exe -m timeit "list(x for x in range(10000))"
2000 loops, best of 5: 188 usec per loop
❯ ./python.exe -m timeit "set(x for x in range(10000))"
1000 loops, best of 5: 226 usec per loop

After:

❯ ./python.exe -m timeit "list(x for x in range(10000))"
2000 loops, best of 5: 150 usec per loop
❯ ./python.exe -m timeit "set(x for x in range(10000))"
2000 loops, best of 5: 178 usec per loop
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kumaraditya303 requested review from Fidget-Spinner and brandtbucher December 23, 2025 08:17
@markshannon

markshannon commented Dec 23, 2025

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This looks promising.

@kumaraditya303 can you benchmark this with small sequences, as those tend to more common.

@iritkatriel could you take a look, as author of the tuple/any/all optimization.
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@kumaraditya303

kumaraditya303 commented Dec 23, 2025

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can you benchmark this with small sequences, as those tend to more common.

Benchmark with smaller sequence:
Before:

❯ ./python.exe -m timeit "list(x for x in range(25))" 
500000 loops, best of 5: 483 nsec per loop

After:

 ❯ ./python.exe -m timeit "list(x for x in range(25))" 
500000 loops, best of 5: 390 nsec per loop
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@kumaraditya303
Merge branch 'main' of https://github.com/python/cpython into optimiz…
2dbe6fc 
…e-list-set
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kumaraditya303 commented Jan 5, 2026

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@markshannon I have fixed the merge conflicts, can you review this?
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markshannon
markshannon approved these changes Jan 6, 2026
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Looks good. Thanks.

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@bedevere-app bedevere-app Bot added awaiting merge and removed awaiting core review labels Jan 6, 2026
@kumaraditya303
kumaraditya303 merged commit 74bb3ca into python:main Jan 6, 2026
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@kumaraditya303
kumaraditya303 deleted the optimize-list-set branch January 6, 2026 17:53
@bedevere-app bedevere-app Bot removed the awaiting merge label Jan 6, 2026
@kumaraditya303 kumaraditya303 mentioned this pull request Jan 13, 2026
Broader specialization in the Specializing Adaptive Interpreter for better JIT performance #143732
Open
thunder-coding pushed a commit to thunder-coding/cpython that referenced this pull request Feb 15, 2026
@kumaraditya303 @thunder-coding
pythongh-142863: optimize list and set calls with generator expre…
916f287 
…ssions (python#142864)
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@markshannon markshannon markshannon approved these changes
@ericsnowcurrently ericsnowcurrently Awaiting requested review from ericsnowcurrently ericsnowcurrently is a code owner
@ZeroIntensity ZeroIntensity Awaiting requested review from ZeroIntensity ZeroIntensity is a code owner
@iritkatriel iritkatriel Awaiting requested review from iritkatriel iritkatriel is a code owner
@Fidget-Spinner Fidget-Spinner Awaiting requested review from Fidget-Spinner
@brandtbucher brandtbucher Awaiting requested review from brandtbucher

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@kumaraditya303 @markshannon
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