try_element_at

Collection function: Returns element of array at given (1-based) index or value for given key in a map. For arrays, if index is 0, Spark will throw an error. If index < 0, accesses elements from the last to the first. The function always returns NULL if the index exceeds the length of the array. For maps, the function always returns NULL if the key is not contained in the map.

For the corresponding Databricks SQL function, see try_element_at function.

Syntax

Python

from pyspark.databricks.sql import functions as dbf

dbf.try_element_at(col=<col>, extraction=<extraction>)

Parameters

Parameter	Type	Description
col	pyspark.sql.Column or str	Name of column containing array or map.
extraction	pyspark.sql.Column or str	Index to check for in array or key to check for in map.

Examples

Example 1: Getting the first element of an array

Python

from pyspark.databricks.sql import functions as dbf
df = spark.createDataFrame([(["a", "b", "c"],)], ['data'])
df.select(dbf.try_element_at(df.data, dbf.lit(1))).show()

Output

+-----------------------+
|try_element_at(data, 1)|
+-----------------------+
|                      a|
+-----------------------+

Example 2: Getting the last element of an array using negative index

Python

from pyspark.databricks.sql import functions as dbf
df = spark.createDataFrame([(["a", "b", "c"],)], ['data'])
df.select(dbf.try_element_at(df.data, dbf.lit(-1))).show()

Output

+------------------------+
|try_element_at(data, -1)|
+------------------------+
|                       c|
+------------------------+