xinrong-databricks commented on code in PR #36464: URL: https://github.com/apache/spark/pull/36464#discussion_r869454838
########## python/pyspark/pandas/groupby.py: ########## @@ -2121,11 +2121,22 @@ def _limit(self, n: int, asc: bool) -> FrameLike: ) ) - sdf = ( - sdf.withColumn(tmp_col, F.row_number().over(window)) - .filter(F.col(tmp_col) <= n) - .drop(tmp_col) - ) + if n >= 0 or LooseVersion(pd.__version__) < LooseVersion("1.4.0"): + sdf = ( + sdf.withColumn(tmp_row_num_col, F.row_number().over(window)) + .filter(F.col(tmp_row_num_col) <= n) + .drop(tmp_row_num_col) + ) + else: + # Pandas supports Groupby positional indexing since v1.4.0 + # https://pandas.pydata.org/docs/whatsnew/v1.4.0.html#groupby-positional-indexing + tmp_cnt_col = verify_temp_column_name(sdf, "__group_count__") + sdf = ( + sdf.withColumn(tmp_row_num_col, F.row_number().over(window)) + .withColumn(tmp_cnt_col, F.count("*").over(Window.partitionBy(*groupkey_scols))) Review Comment: nit: We may also extract `Window.partitionBy(*groupkey_scols)` as a variable since there are 3 uses in this function. Meanwhile, renaming `window` to be more specific may help understand the code. The current code looks good enough if you prefer not to change it. -- 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