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Posted to reviews@spark.apache.org by GitBox <gi...@apache.org> on 2022/09/19 07:24:17 UTC

[GitHub] [spark] Yikun commented on a diff in pull request #37923: [SPARK-40334][PS] Implement `GroupBy.prod`

Yikun commented on code in PR #37923:
URL: https://github.com/apache/spark/pull/37923#discussion_r973821134


##########
python/pyspark/pandas/groupby.py:
##########
@@ -993,6 +993,98 @@ def nth(self, n: int) -> FrameLike:
 
         return self._prepare_return(DataFrame(internal))
 
+    def prod(self, numeric_only: Optional[bool] = True, min_count: int = 0):
+        """
+        Compute prod of groups.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+        Include only float, int, boolean columns. If None, will attempt to use
+        everything, then use only numeric data.
+
+        min_count: int, default 0
+        The required number of valid values to perform the operation.
+        If fewer than min_count non-NA values are present the result will be NA.
+
+        .. versionadded:: 3.4.0
+
+        Returns
+        -------
+        pyspark.pandas.Series or pyspark.pandas.DataFrame
+
+        See Also
+        --------
+        pyspark.pandas.Series.groupby
+        pyspark.pandas.DataFrame.groupby
+
+        Examples
+        --------
+        >>> df = ps.DataFrame({'A': [1, 1, 2, 1, 2],
+        ...                    'B': [np.nan, 2, 3, 4, 5],
+        ...                    'C': [1, 2, 1, 1, 2],
+        ...                    'D': [True, False, True, False, True]})
+
+        Groupby one column and return the prod of the remaining columns in
+        each group.
+
+        >>> df.groupby('A').prod().sort_index()
+             B  C  D
+        A
+        1  8.0  2  0
+        2  15.0 2  11
+
+        >>> df.groupby('A').prod(min_count=3).sort_index()
+             B  C   D
+        A
+        1  NaN  2  0

Review Comment:
   ```suggestion
           1  NaN  2.0  0.0
   ```



##########
python/pyspark/pandas/groupby.py:
##########
@@ -61,7 +61,7 @@
     NumericType,
     StructField,
     StructType,
-    StringType,
+    StringType, IntegralType,

Review Comment:
   ```suggestion
       StringType,
       IntegralType,
   ```



##########
python/pyspark/pandas/groupby.py:
##########
@@ -993,6 +993,98 @@ def nth(self, n: int) -> FrameLike:
 
         return self._prepare_return(DataFrame(internal))
 
+    def prod(self, numeric_only: Optional[bool] = True, min_count: int = 0):
+        """
+        Compute prod of groups.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+        Include only float, int, boolean columns. If None, will attempt to use
+        everything, then use only numeric data.
+
+        min_count: int, default 0
+        The required number of valid values to perform the operation.
+        If fewer than min_count non-NA values are present the result will be NA.
+
+        .. versionadded:: 3.4.0
+
+        Returns
+        -------
+        pyspark.pandas.Series or pyspark.pandas.DataFrame
+
+        See Also
+        --------
+        pyspark.pandas.Series.groupby
+        pyspark.pandas.DataFrame.groupby
+
+        Examples
+        --------
+        >>> df = ps.DataFrame({'A': [1, 1, 2, 1, 2],
+        ...                    'B': [np.nan, 2, 3, 4, 5],
+        ...                    'C': [1, 2, 1, 1, 2],
+        ...                    'D': [True, False, True, False, True]})
+
+        Groupby one column and return the prod of the remaining columns in
+        each group.
+
+        >>> df.groupby('A').prod().sort_index()
+             B  C  D
+        A
+        1  8.0  2  0
+        2  15.0 2  11
+
+        >>> df.groupby('A').prod(min_count=3).sort_index()
+             B  C   D
+        A
+        1  NaN  2  0
+        2  NaN NaN  NaN
+        """
+
+        self._validate_agg_columns(numeric_only=numeric_only, function_name="prod")
+
+        groupkey_names = [SPARK_INDEX_NAME_FORMAT(i) for i in range(len(self._groupkeys))]
+        internal, agg_columns, sdf = self._prepare_reduce(
+            groupkey_names=groupkey_names,
+            accepted_spark_types=(NumericType, BooleanType),
+            bool_to_numeric=True,
+        )
+
+        psdf: DataFrame = DataFrame(internal)
+        if len(psdf._internal.column_labels) > 0:
+
+            stat_exprs = []
+            for label in psdf._internal.column_labels:
+                psser = psdf._psser_for(label)
+                column = psser._dtype_op.nan_to_null(psser).spark.column
+                data_type = psser.spark.data_type
+
+                if isinstance(data_type, IntegralType):
+                    stat_exprs.append(F.product(column).cast(data_type).alias(f"{label[0]}"))
+                else:
+                    stat_exprs.append(F.product(column).alias(f"{label[0]}"))
+
+                stat_exprs.append(F.count(column).alias(f"{label[0]}_count"))

Review Comment:
   Looks like we also don't need this helper column if min_count==0, right?



##########
python/pyspark/pandas/groupby.py:
##########
@@ -993,6 +993,98 @@ def nth(self, n: int) -> FrameLike:
 
         return self._prepare_return(DataFrame(internal))
 
+    def prod(self, numeric_only: Optional[bool] = True, min_count: int = 0):
+        """
+        Compute prod of groups.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+        Include only float, int, boolean columns. If None, will attempt to use
+        everything, then use only numeric data.
+
+        min_count: int, default 0
+        The required number of valid values to perform the operation.
+        If fewer than min_count non-NA values are present the result will be NA.
+
+        .. versionadded:: 3.4.0
+
+        Returns
+        -------
+        pyspark.pandas.Series or pyspark.pandas.DataFrame
+
+        See Also
+        --------
+        pyspark.pandas.Series.groupby
+        pyspark.pandas.DataFrame.groupby
+
+        Examples
+        --------
+        >>> df = ps.DataFrame({'A': [1, 1, 2, 1, 2],
+        ...                    'B': [np.nan, 2, 3, 4, 5],
+        ...                    'C': [1, 2, 1, 1, 2],
+        ...                    'D': [True, False, True, False, True]})
+
+        Groupby one column and return the prod of the remaining columns in
+        each group.
+
+        >>> df.groupby('A').prod().sort_index()
+             B  C  D
+        A
+        1  8.0  2  0
+        2  15.0 2  11

Review Comment:
   ```suggestion
           2  15.0 2  1
   ```



##########
python/pyspark/pandas/groupby.py:
##########
@@ -993,6 +993,98 @@ def nth(self, n: int) -> FrameLike:
 
         return self._prepare_return(DataFrame(internal))
 
+    def prod(self, numeric_only: Optional[bool] = True, min_count: int = 0):
+        """
+        Compute prod of groups.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+        Include only float, int, boolean columns. If None, will attempt to use
+        everything, then use only numeric data.

Review Comment:
   ```suggestion
           numeric_only : bool, default False
               Include only float, int, boolean columns. If None, will attempt to use
               everything, then use only numeric data.
   ```



##########
python/pyspark/pandas/groupby.py:
##########
@@ -993,6 +993,98 @@ def nth(self, n: int) -> FrameLike:
 
         return self._prepare_return(DataFrame(internal))
 
+    def prod(self, numeric_only: Optional[bool] = True, min_count: int = 0):
+        """
+        Compute prod of groups.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+        Include only float, int, boolean columns. If None, will attempt to use
+        everything, then use only numeric data.
+
+        min_count: int, default 0
+        The required number of valid values to perform the operation.
+        If fewer than min_count non-NA values are present the result will be NA.

Review Comment:
   ```suggestion
           min_count: int, default 0
               The required number of valid values to perform the operation.
               If fewer than min_count non-NA values are present the result will be NA.
   ```



##########
python/pyspark/pandas/groupby.py:
##########
@@ -993,6 +993,98 @@ def nth(self, n: int) -> FrameLike:
 
         return self._prepare_return(DataFrame(internal))
 
+    def prod(self, numeric_only: Optional[bool] = True, min_count: int = 0):
+        """
+        Compute prod of groups.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+        Include only float, int, boolean columns. If None, will attempt to use
+        everything, then use only numeric data.
+
+        min_count: int, default 0
+        The required number of valid values to perform the operation.
+        If fewer than min_count non-NA values are present the result will be NA.
+
+        .. versionadded:: 3.4.0

Review Comment:
   You might want to move this before `Parameters`



##########
python/pyspark/pandas/groupby.py:
##########
@@ -993,6 +993,98 @@ def nth(self, n: int) -> FrameLike:
 
         return self._prepare_return(DataFrame(internal))
 
+    def prod(self, numeric_only: Optional[bool] = True, min_count: int = 0):
+        """
+        Compute prod of groups.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+        Include only float, int, boolean columns. If None, will attempt to use
+        everything, then use only numeric data.
+
+        min_count: int, default 0
+        The required number of valid values to perform the operation.
+        If fewer than min_count non-NA values are present the result will be NA.
+
+        .. versionadded:: 3.4.0
+
+        Returns
+        -------
+        pyspark.pandas.Series or pyspark.pandas.DataFrame
+
+        See Also
+        --------
+        pyspark.pandas.Series.groupby
+        pyspark.pandas.DataFrame.groupby
+
+        Examples
+        --------
+        >>> df = ps.DataFrame({'A': [1, 1, 2, 1, 2],
+        ...                    'B': [np.nan, 2, 3, 4, 5],
+        ...                    'C': [1, 2, 1, 1, 2],
+        ...                    'D': [True, False, True, False, True]})
+
+        Groupby one column and return the prod of the remaining columns in
+        each group.
+
+        >>> df.groupby('A').prod().sort_index()
+             B  C  D
+        A
+        1  8.0  2  0
+        2  15.0 2  11
+
+        >>> df.groupby('A').prod(min_count=3).sort_index()
+             B  C   D
+        A
+        1  NaN  2  0
+        2  NaN NaN  NaN
+        """
+
+        self._validate_agg_columns(numeric_only=numeric_only, function_name="prod")
+
+        groupkey_names = [SPARK_INDEX_NAME_FORMAT(i) for i in range(len(self._groupkeys))]
+        internal, agg_columns, sdf = self._prepare_reduce(
+            groupkey_names=groupkey_names,
+            accepted_spark_types=(NumericType, BooleanType),
+            bool_to_numeric=True,
+        )
+
+        psdf: DataFrame = DataFrame(internal)
+        if len(psdf._internal.column_labels) > 0:
+
+            stat_exprs = []
+            for label in psdf._internal.column_labels:
+                psser = psdf._psser_for(label)
+                column = psser._dtype_op.nan_to_null(psser).spark.column
+                data_type = psser.spark.data_type
+
+                if isinstance(data_type, IntegralType):
+                    stat_exprs.append(F.product(column).cast(data_type).alias(f"{label[0]}"))
+                else:
+                    stat_exprs.append(F.product(column).alias(f"{label[0]}"))
+
+                stat_exprs.append(F.count(column).alias(f"{label[0]}_count"))
+
+            sdf = sdf.groupby(*groupkey_names).agg(*stat_exprs)
+
+            if min_count > 0:
+                for label in psdf._internal.column_labels:
+                    sdf = sdf.withColumn(f"{label[0]}", F.when(F.col(f"{label[0]}_count").__ge__(min_count),

Review Comment:
   we usually choose to create a temporary column with a special name and verify (`verify_temp_column_name`), and then drop it.
   
   see below as reference:
   https://github.com/apache/spark/blob/master/python/pyspark/pandas/groupby.py#L1024-L1032



##########
python/pyspark/pandas/groupby.py:
##########
@@ -993,6 +993,98 @@ def nth(self, n: int) -> FrameLike:
 
         return self._prepare_return(DataFrame(internal))
 
+    def prod(self, numeric_only: Optional[bool] = True, min_count: int = 0):
+        """
+        Compute prod of groups.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+        Include only float, int, boolean columns. If None, will attempt to use
+        everything, then use only numeric data.
+
+        min_count: int, default 0
+        The required number of valid values to perform the operation.
+        If fewer than min_count non-NA values are present the result will be NA.
+
+        .. versionadded:: 3.4.0
+
+        Returns
+        -------
+        pyspark.pandas.Series or pyspark.pandas.DataFrame
+
+        See Also
+        --------
+        pyspark.pandas.Series.groupby
+        pyspark.pandas.DataFrame.groupby
+
+        Examples
+        --------
+        >>> df = ps.DataFrame({'A': [1, 1, 2, 1, 2],
+        ...                    'B': [np.nan, 2, 3, 4, 5],
+        ...                    'C': [1, 2, 1, 1, 2],
+        ...                    'D': [True, False, True, False, True]})
+
+        Groupby one column and return the prod of the remaining columns in
+        each group.
+
+        >>> df.groupby('A').prod().sort_index()
+             B  C  D
+        A
+        1  8.0  2  0
+        2  15.0 2  11
+
+        >>> df.groupby('A').prod(min_count=3).sort_index()
+             B  C   D
+        A
+        1  NaN  2  0
+        2  NaN NaN  NaN
+        """
+
+        self._validate_agg_columns(numeric_only=numeric_only, function_name="prod")
+
+        groupkey_names = [SPARK_INDEX_NAME_FORMAT(i) for i in range(len(self._groupkeys))]
+        internal, agg_columns, sdf = self._prepare_reduce(
+            groupkey_names=groupkey_names,
+            accepted_spark_types=(NumericType, BooleanType),
+            bool_to_numeric=True,
+        )
+
+        psdf: DataFrame = DataFrame(internal)
+        if len(psdf._internal.column_labels) > 0:
+
+            stat_exprs = []
+            for label in psdf._internal.column_labels:
+                psser = psdf._psser_for(label)
+                column = psser._dtype_op.nan_to_null(psser).spark.column
+                data_type = psser.spark.data_type
+
+                if isinstance(data_type, IntegralType):
+                    stat_exprs.append(F.product(column).cast(data_type).alias(f"{label[0]}"))

Review Comment:
   nit:
   > let's don't use f-format. we dropped Python 3.5 so it's technically fine but I think it's better to don't break that support only because of this one string format.
   
   https://github.com/apache/spark/pull/36509#discussion_r874263076



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