Use _values_for_factorize by default for hashing ExtensionArrays #53475
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jorisvandenbossche
added
the
ExtensionArray
Member
Author
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@jbrockmendel are you OK with this? |
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No objections. |
This comment was marked as outdated.
This comment was marked as outdated.
Member
Author
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Sorry for the backport noise, the original PR was only for 2.1, so of course this fixup only needs to target 2.1 as well |
Contributor
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Does this need a whatsnew? This looks like only a regression on main. |
Member
Author
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Good catch, sorry! I only realized after merging it was only a change on main and thus didn't need to be backported, but forgot that I actually added a whatsnew ... |
Daquisu
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to Daquisu/pandas
that referenced
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Jul 8, 2023
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PR #51319 added the
EA._hash_pandas_objectmethod to let ExtensionArrays override how they are hashed. But it also changed to no longer use the values returned byEA._values_for_factorize()by default for hashing, but change this toEA.to_numpy(). The previous behaviour was documented, and changing this can cause regressions / changes in behaviour or performance (depending on the return values of those two methods).See https://github.com/pandas-dev/pandas/pull/51319/files#r1212106303 for some more details.