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ENH: Improve ref-tracking for group keys #51442

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Merged
merged 7 commits into from
Feb 20, 2023
Merged

ENH: Improve ref-tracking for group keys #51442

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ENH: Improve ref-tracking for group keys
phofl Feb 16, 2023
fb7915a
Merge branch 'main' into cow_groupby_ref_tracking
phofl Feb 16, 2023
c2c77c6
Fix
phofl Feb 16, 2023
0873d50
Refactor
phofl Feb 17, 2023
b7270b4
Address review
phofl Feb 17, 2023
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Address review
phofl Feb 17, 2023
7f9effb
Merge remote-tracking branch 'upstream/main' into cow_groupby_ref_tra…
phofl Feb 17, 2023
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7 changes: 6 additions & 1 deletion pandas/core/groupby/grouper.py
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@
final,
)
import warnings
import weakref

import numpy as np

Expand Down Expand Up @@ -947,9 +948,13 @@ def is_in_obj(gpr) -> bool:
# For the CoW case, we need an equality check as the identity check
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Can you update this comment?

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Done

# no longer works (each Series from column access is a new object)
try:
return gpr.equals(obj[gpr.name])
obj_gpr_column = obj[gpr.name]
except (AttributeError, KeyError, IndexError, InvalidIndexError):
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You can remove the AttributeError now, I think (.name is already checked above)

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Correct, thx

return False
if isinstance(gpr, Series) and isinstance(obj_gpr_column, Series):
ref = weakref.ref(obj_gpr_column._mgr.blocks[0])
return ref in gpr._mgr.blocks[0].refs.referenced_blocks
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So if you create multiple times a weakref to the same object, this is always the same (i.e. identical) weakref object?

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Yep, that's how it is documented (https://docs.python.org/3/library/weakref.html#weakref.ref). Did some basic checks with out blocks and it works as I would have expected

return False
try:
return gpr is obj[gpr.name]
except (KeyError, IndexError, InvalidIndexError):
Expand Down