map_keys

Returns an unordered array containing the keys of the map.

Syntax

from pyspark.sql import functions as sf

sf.map_keys(col)

Parameters

Parameter	Type	Description
col	pyspark.sql.Column or str	Name of column or expression

Returns

pyspark.sql.Column: Keys of the map as an array.

Examples

Example 1: Extracting keys from a simple map

from pyspark.sql import functions as sf
df = spark.sql("SELECT map(1, 'a', 2, 'b') as data")
df.select(sf.sort_array(sf.map_keys("data"))).show()

+--------------------------------+
|sort_array(map_keys(data), true)|
+--------------------------------+
|                          [1, 2]|
+--------------------------------+

Example 2: Extracting keys from a map with complex keys

from pyspark.sql import functions as sf
df = spark.sql("SELECT map(array(1, 2), 'a', array(3, 4), 'b') as data")
df.select(sf.sort_array(sf.map_keys("data"))).show()

+--------------------------------+
|sort_array(map_keys(data), true)|
+--------------------------------+
|                [[1, 2], [3, 4]]|
+--------------------------------+

Example 3: Extracting keys from an empty map

from pyspark.sql import functions as sf
df = spark.sql("SELECT map() as data")
df.select(sf.map_keys("data")).show()

+--------------+
|map_keys(data)|
+--------------+
|            []|
+--------------+