PERF: Merge empty frame #45838
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PERF: Merge empty frame #45838
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lukemanley
added
Performance
jreback
requested changes
Feb 5, 2022
asv_bench/benchmarks/join_merge.py
Outdated
| @@ -216,6 +216,9 @@ def time_merge_dataframe_integer_2key(self, sort): | |||
| def time_merge_dataframe_integer_key(self, sort): | |||
| merge(self.df, self.df2, on="key1", sort=sort) | |||
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| def time_merge_dataframe_empty(self, sort): | |||
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can you add the reverse as well (e.g. left empty)
phofl
reviewed
Feb 6, 2022
doc/source/whatsnew/v1.5.0.rst
Outdated
| @@ -206,6 +206,7 @@ Performance improvements | |||
| - Performance improvement in :meth:`DataFrame.duplicated` when subset consists of only one column (:issue:`45236`) | |||
| - Performance improvement in :meth:`.GroupBy.transform` when broadcasting values for user-defined functions (:issue:`45708`) | |||
| - Performance improvement in :meth:`.GroupBy.transform` for user-defined functions when only a single group exists (:issue:`44977`) | |||
| - Performance improvement in :meth:`DataFrame.merge` when left and/or right are empty (:issue:`45838`) | |||
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I think we normally use :func: merge instead of DataFrame.merge?
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updated to :func: merge. thanks
jreback
approved these changes
Feb 9, 2022
|
lgtm will merge on green. tip to avoid conflicts in the release notes; add a note not at the bottom, add in middle somewhere |
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Greenish |
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Thx @lukemanley |
phofl
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Feb 14, 2022
* faster merge with empty frame * whatsnew * docs, tests, asvs * fix whatsnew Co-authored-by: Jeff Reback <[email protected]>
yehoshuadimarsky
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Jul 13, 2022
* faster merge with empty frame * whatsnew * docs, tests, asvs * fix whatsnew Co-authored-by: Jeff Reback <[email protected]>
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doc/source/whatsnew/vX.X.X.rstfile if fixing a bug or adding a new feature.Faster merge when left or right is empty.
One ASV added:
Some additional examples: