amaliujia commented on code in PR #38858:
URL: https://github.com/apache/spark/pull/38858#discussion_r1036698430
##########
python/pyspark/sql/connect/functions.py:
##########
@@ -16,14 +16,247 @@
#
from pyspark.sql.connect.column import Column, LiteralExpression,
ColumnReference
-from typing import Any
+from typing import Any, TYPE_CHECKING
+
+if TYPE_CHECKING:
+ from pyspark.sql.connect._typing import ColumnOrName
# TODO(SPARK-40538) Add support for the missing PySpark functions.
+def _to_col(col: "ColumnOrName") -> Column:
+ return col if isinstance(col, Column) else column(col)
+
+
def col(x: str) -> Column:
return Column(ColumnReference(x))
+column = col
+
+
def lit(x: Any) -> Column:
return Column(LiteralExpression(x))
+
+
+def asc(col: "ColumnOrName") -> Column:
+ """
+ Returns a sort expression based on the ascending order of the given column
name.
+
+ .. versionadded:: 3.4.0
+
+ Parameters
+ ----------
+ col : :class:`~pyspark.sql.Column` or str
+ target column to sort by in the ascending order.
+
+ Returns
+ -------
+ :class:`~pyspark.sql.Column`
+ the column specifying the order.
+
+ Examples
+ --------
+ Sort by the column 'id' in the descending order.
+
+ >>> df = spark.range(5)
+ >>> df = df.sort(desc("id"))
+ >>> df.show()
+ +---+
+ | id|
+ +---+
+ | 4|
+ | 3|
+ | 2|
+ | 1|
+ | 0|
+ +---+
+
+ Sort by the column 'id' in the ascending order.
+
+ >>> df.orderBy(asc("id")).show()
+ +---+
+ | id|
+ +---+
+ | 0|
+ | 1|
+ | 2|
+ | 3|
+ | 4|
+ +---+
+ """
+ return _to_col(col).asc()
+
+
+def asc_nulls_first(col: "ColumnOrName") -> Column:
+ """
+ Returns a sort expression based on the ascending order of the given
+ column name, and null values return before non-null values.
+
+ .. versionadded:: 2.4.0
+
+ Parameters
+ ----------
+ col : :class:`~pyspark.sql.Column` or str
+ target column to sort by in the ascending order.
+
+ Returns
+ -------
+ :class:`~pyspark.sql.Column`
+ the column specifying the order.
+
+ Examples
+ --------
+ >>> df1 = spark.createDataFrame([(1, "Bob"),
+ ... (0, None),
+ ... (2, "Alice")], ["age", "name"])
+ >>> df1.sort(asc_nulls_first(df1.name)).show()
+ +---+-----+
+ |age| name|
+ +---+-----+
+ | 0| null|
+ | 2|Alice|
+ | 1| Bob|
+ +---+-----+
+
+ """
+ return _to_col(col).asc_nulls_first()
+
+
+def asc_nulls_last(col: "ColumnOrName") -> Column:
+ """
+ Returns a sort expression based on the ascending order of the given
+ column name, and null values appear after non-null values.
+
+ .. versionadded:: 2.4.0
Review Comment:
nit: wrong `versionadded`. BTW do we need always add `versionadded 3.4.0`
given the entire package is `versionadded`? Maybe only need a top level
`versionadded`?
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