HyukjinKwon commented on a change in pull request #33634: URL: https://github.com/apache/spark/pull/33634#discussion_r683915361
########## File path: python/pyspark/pandas/indexes/base.py ########## @@ -2292,9 +2292,7 @@ def union( sdf_self = self._internal.spark_frame.select(self._internal.index_spark_columns) sdf_other = other_idx._internal.spark_frame.select(other_idx._internal.index_spark_columns) - sdf = sdf_self.union(sdf_other.subtract(sdf_self)) - if isinstance(self, MultiIndex): - sdf = sdf.drop_duplicates() + sdf = sdf_self.unionAll(sdf_other).exceptAll(sdf_self.intersectAll(sdf_other)) if sort: Review comment: @itholic, did you refer to this? > Bug in Index.union() and MultiIndex.union() dropping duplicate Index values when Index was not monotonic or sort was set to False (GH36289, GH31326, GH40862) It sounds like now it drops duplicates but the codes above in Pr description look keeping the duplicates. Should we also at least check `sort` and drop duplicates? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org