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Returns a sort expression based on the ascending order of the given column name, and null values return before non-null values. Supports Spark Connect.
Syntax
from pyspark.databricks.sql import functions as dbf
dbf.asc_nulls_first(col=<col>)
Parameters
| Parameter | Type | Description |
|---|---|---|
col |
pyspark.sql.Column or str |
Target column to sort by in the ascending order. |
Returns
pyspark.sql.Column: the column specifying the order.
Examples
Example 1: Sorting a DataFrame with null values in ascending order.
from pyspark.databricks.sql import functions as dbf
df = spark.createDataFrame([(1, "Bob"), (0, None), (2, "Alice")], ["age", "name"])
df.sort(dbf.asc_nulls_first(df.name)).show()
+---+-----+
|age| name|
+---+-----+
| 0| NULL|
| 2|Alice|
| 1| Bob|
+---+-----+
Example 2: Sorting a DataFrame with null values in ascending order using column name string.
from pyspark.databricks.sql import functions as dbf
df = spark.createDataFrame([(1, "Bob"), (0, None), (2, "Alice")], ["age", "name"])
df.sort(dbf.asc_nulls_first("name")).show()
+---+-----+
|age| name|
+---+-----+
| 0| NULL|
| 2|Alice|
| 1| Bob|
+---+-----+