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Posted to reviews@spark.apache.org by GitBox <gi...@apache.org> on 2021/09/01 09:26:04 UTC
[GitHub] [spark] xinrong-databricks commented on a change in pull request #33858: [SPARK-36402][PYTHON] Implement Series.combine
xinrong-databricks commented on a change in pull request #33858:
URL: https://github.com/apache/spark/pull/33858#discussion_r699660235
##########
File path: python/pyspark/pandas/series.py
##########
@@ -4425,6 +4427,127 @@ def replace(
return self._with_new_scol(current) # TODO: dtype?
+ def combine(
+ self,
+ other: "Series",
+ func: Callable,
+ fill_value: Optional[Any] = None,
+ return_type: Optional[Union[str, DataType]] = "string",
+ ) -> "Series":
+ """
+ Combine the Series with a Series or scalar according to `func`.
+ Combine the Series and `other` using `func` to perform elementwise
+ selection for combined Series.
+ `fill_value` is assumed when value is missing at some index
+ from one of the two objects being combined.
+
+ Parameters
+ ----------
+ other : Series or scalar
+ The value(s) to be combined with the `Series`.
+ func : function
+ Function that takes two scalars as inputs and returns an element.
+ fill_value : scalar, optional
+ The value to assume when an index is missing from
+ one Series or the other. The default specifies to use the
+ appropriate NaN value for the underlying dtype of the Series.
+ return_type : :class:`pyspark.sql.types.DataType` or str
+ the return type of the output Series. The value can be either a
+ :class:`pyspark.sql.types.DataType` object or a DDL-formatted type string.
+
+ Returns
+ -------
+ Series
+ The result of combining the Series with the other object.
+
+ See Also
+ --------
+ Series.combine_first : Combine Series values, choosing the calling
+ Series' values first.
+
+ Examples
+ --------
+ Consider 2 Datasets ``s1`` and ``s2`` containing
+ highest clocked speeds of different birds.
+
+ >>> from pyspark.pandas.config import set_option, reset_option
+ >>> set_option("compute.ops_on_diff_frames", True)
+ >>> s1 = ps.Series({'falcon': 330.0, 'eagle': 160.0})
+ >>> s1
+ falcon 330.0
+ eagle 160.0
+ dtype: float64
+ >>> s2 = ps.Series({'falcon': 345.0, 'eagle': 200.0, 'duck': 30.0})
+ >>> s2
+ falcon 345.0
+ eagle 200.0
+ duck 30.0
+ dtype: float64
+
+ Now, to combine the two datasets and view the highest speeds
+ of the birds across the two datasets
+
+ >>> s1.combine(s2, max, return_type="double")
+ duck NaN
+ eagle 200.0
+ falcon 345.0
+ dtype: float64
+
+ In the previous example, the resulting value for duck is missing,
+ because the maximum of a NaN and a float is a NaN.
+ So, in the example, we set ``fill_value=0``,
+ so the maximum value returned will be the value from some dataset.
+
+ >>> s1.combine(s2, max, fill_value=0, return_type="double")
+ duck 30.0
+ eagle 200.0
+ falcon 345.0
+ dtype: float64
+ >>> reset_option("compute.ops_on_diff_frames")
+ """
+ if not isinstance(other, Series) and not np.isscalar(other):
+ raise TypeError("unsupported type: %s" % type(other))
+
+ if np.isscalar(other):
+ combined = DataFrame(
+ InternalFrame(
+ spark_frame=self._internal.spark_frame.withColumn("__other", SF.lit(other)),
Review comment:
Shall we verify `__other` by https://github.com/apache/spark/blob/master/python/pyspark/pandas/utils.py#L795?
##########
File path: python/pyspark/pandas/series.py
##########
@@ -4425,6 +4427,127 @@ def replace(
return self._with_new_scol(current) # TODO: dtype?
+ def combine(
+ self,
+ other: "Series",
+ func: Callable,
+ fill_value: Optional[Any] = None,
+ return_type: Optional[Union[str, DataType]] = "string",
+ ) -> "Series":
+ """
+ Combine the Series with a Series or scalar according to `func`.
+ Combine the Series and `other` using `func` to perform elementwise
+ selection for combined Series.
+ `fill_value` is assumed when value is missing at some index
+ from one of the two objects being combined.
+
+ Parameters
+ ----------
+ other : Series or scalar
+ The value(s) to be combined with the `Series`.
+ func : function
+ Function that takes two scalars as inputs and returns an element.
+ fill_value : scalar, optional
+ The value to assume when an index is missing from
+ one Series or the other. The default specifies to use the
+ appropriate NaN value for the underlying dtype of the Series.
+ return_type : :class:`pyspark.sql.types.DataType` or str
+ the return type of the output Series. The value can be either a
+ :class:`pyspark.sql.types.DataType` object or a DDL-formatted type string.
+
+ Returns
+ -------
+ Series
+ The result of combining the Series with the other object.
+
+ See Also
+ --------
+ Series.combine_first : Combine Series values, choosing the calling
+ Series' values first.
+
+ Examples
+ --------
+ Consider 2 Datasets ``s1`` and ``s2`` containing
+ highest clocked speeds of different birds.
+
+ >>> from pyspark.pandas.config import set_option, reset_option
+ >>> set_option("compute.ops_on_diff_frames", True)
+ >>> s1 = ps.Series({'falcon': 330.0, 'eagle': 160.0})
+ >>> s1
+ falcon 330.0
+ eagle 160.0
+ dtype: float64
+ >>> s2 = ps.Series({'falcon': 345.0, 'eagle': 200.0, 'duck': 30.0})
+ >>> s2
+ falcon 345.0
+ eagle 200.0
+ duck 30.0
+ dtype: float64
+
+ Now, to combine the two datasets and view the highest speeds
+ of the birds across the two datasets
+
+ >>> s1.combine(s2, max, return_type="double")
+ duck NaN
+ eagle 200.0
+ falcon 345.0
+ dtype: float64
+
+ In the previous example, the resulting value for duck is missing,
+ because the maximum of a NaN and a float is a NaN.
+ So, in the example, we set ``fill_value=0``,
+ so the maximum value returned will be the value from some dataset.
+
+ >>> s1.combine(s2, max, fill_value=0, return_type="double")
+ duck 30.0
+ eagle 200.0
+ falcon 345.0
+ dtype: float64
+ >>> reset_option("compute.ops_on_diff_frames")
+ """
+ if not isinstance(other, Series) and not np.isscalar(other):
+ raise TypeError("unsupported type: %s" % type(other))
+
+ if np.isscalar(other):
+ combined = DataFrame(
+ InternalFrame(
+ spark_frame=self._internal.spark_frame.withColumn("__other", SF.lit(other)),
+ index_spark_columns=self._internal.index_spark_columns,
+ )
+ )
+ else:
+ combined = (
+ self._psdf[self._column_label, other._column_label]
+ if same_anchor(self, other)
+ else combine_frames(self.to_frame(), other.to_frame())
+ )
+
+ sdf = combined._internal.spark_frame
+ if fill_value is not None:
+ sdf = sdf.fillna(fill_value)
+
+ @udf
Review comment:
What's the concern about not using pandas_udf here?
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