Notiz
Zougrëff op dës Säit erfuerdert Autorisatioun. Dir kënnt probéieren, Iech unzemellen oder Verzeechnesser ze änneren.
Zougrëff op dës Säit erfuerdert Autorisatioun. Dir kënnt probéieren, Verzeechnesser ze änneren.
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)|
+--------------+
| []|
+--------------+