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GeezerVison is showing github.com — gh-146151: memoryview supports 'F' and 'D' format types (complex) by skirpichev · Pull Request #146241 · python/cpython

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@skirpichev

@skirpichev skirpichev commented Mar 21, 2026 •
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  • Issue: Support complex (float/double) types in array.array and memoryview #146151

📚 Documentation preview 📚: https://cpython-previews--146241.org.readthedocs.build/

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@skirpichev
pythongh-146151: memoryview supports 'F' and 'D' format types (complex)
94ee023
@skirpichev
skirpichev requested a review from AA-Turner as a code owner March 21, 2026 06:23
@bedevere-app bedevere-app Bot mentioned this pull request Mar 21, 2026
Support complex (float/double) types in array.array and memoryview #146151
Closed
@bedevere-app bedevere-app Bot added the awaiting review label Mar 21, 2026
vstinner
vstinner reviewed Mar 25, 2026
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Comment thread Doc/whatsnew/3.15.rst Resolved

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Comment thread Lib/test/test_memoryview.py Resolved

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skirpichev and others added 3 commits March 26, 2026 02:35
@skirpichev @vstinner
Apply suggestions from code review
c94450e 
Co-authored-by: Victor Stinner <[email protected]>
@skirpichev
Merge branch 'master' into support-complex-memoryview/146151
43e9b18
@skirpichev
address review: add complex test to test_compare_equal()
a728a1b
@skirpichev
skirpichev requested a review from vstinner March 26, 2026 00:11
vstinner
vstinner approved these changes Mar 26, 2026
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LGTM. The implementation looks complete and well tested.

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Comment thread Objects/memoryobject.c
memcpy(ptr, &x, sizeof(x));
}
else {
float x[2] = {(float)c.real, (float)c.imag};

@vstinner vstinner Mar 26, 2026

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I wasn't sure of the behavior on underflow or overflow of the double to float cast, so I tested:

>>> import struct, sys
>>> data=struct.pack('F', 0.0) * 4
>>> m=memoryview(bytearray(data)).cast('F')
>>> m[0]=math.nextafter(0, 1)
>>> m[1]=sys.float_info.min
>>> m[2]=sys.float_info.max
>>> m[3]=float("nan")
>>> m.tolist()
[0j, 0j, (inf+0j), (nan+0j)]

I got the values that I expected. I suppose that these conversions are well specified by IEEE 754.

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@skirpichev skirpichev Mar 26, 2026

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The behavior here is same as for 'f' format, just component-wise, see PACK_SINGLE macro.

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Comment thread Misc/NEWS.d/next/Core_and_Builtins/2026-03-21-08-11-58.gh-issue-146151.4-lhim.rst Resolved

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@bedevere-app bedevere-app Bot added awaiting merge and removed awaiting review labels Mar 26, 2026
@skirpichev @vstinner
Update Misc/NEWS.d/next/Core_and_Builtins/2026-03-21-08-11-58.gh-issu…
f83e88f 
…e-146151.4-lhim.rst

Co-authored-by: Victor Stinner <[email protected]>
@vstinner
vstinner merged commit c68a194 into python:main Mar 26, 2026
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@bedevere-app bedevere-app Bot removed the awaiting merge label Mar 26, 2026
@vstinner

vstinner commented Mar 26, 2026

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Merged, thanks for your contribution.
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@skirpichev
skirpichev deleted the support-complex-memoryview/146151 branch March 26, 2026 18:34
@pablogsal pablogsal mentioned this pull request Apr 4, 2026
gh-130273: Fix traceback color output with unicode characters #142529
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@seberg seberg mentioned this pull request Apr 12, 2026
gh-146151: support for complex arrays in the array module #146237
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clin1234 pushed a commit to clin1234/cpython that referenced this pull request Apr 16, 2026
@skirpichev @vstinner @clin1234
pythongh-146151: memoryview supports 'F' and 'D' format types (comple…
6735afa 
…x) (python#146241)

Co-authored-by: Victor Stinner <[email protected]>
@skirpichev skirpichev mentioned this pull request Apr 17, 2026
Decide buffer protocol format string for complex numbers python/steering-council#345
Closed
skirpichev added a commit to skirpichev/cpython that referenced this pull request Apr 17, 2026
@skirpichev
Revert "pythongh-146151: memoryview supports 'F' and 'D' format types…
760e2f0 
… (complex) (python#146241)"

This reverts commit c68a194.
ljfp pushed a commit to ljfp/cpython that referenced this pull request Apr 25, 2026
@skirpichev @vstinner @ljfp
pythongh-146151: memoryview supports 'F' and 'D' format types (comple…
03415bd 
…x) (python#146241)

Co-authored-by: Victor Stinner <[email protected]>
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@vstinner vstinner vstinner approved these changes
@AA-Turner AA-Turner Awaiting requested review from AA-Turner AA-Turner is a code owner

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@skirpichev @vstinner
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