string_agg
Aggregate function: returns the concatenation of non-null input values, separated by the delimiter. An alias of listagg.
Syntax
Python
from pyspark.sql import functions as sf
sf.string_agg(col, delimiter=None)
Parameters
Parameter | Type | Description |
|---|---|---|
|
| Target column to compute on. |
|
| The delimiter to separate the values. The default value is None. |
Returns
pyspark.sql.Column: the column for computed results.
Examples
Example 1: Using string_agg function
Python
from pyspark.sql import functions as sf
df = spark.createDataFrame([('a',), ('b',), (None,), ('c',)], ['strings'])
df.select(sf.string_agg('strings')).show()
Output
+-------------------------+
|string_agg(strings, NULL)|
+-------------------------+
| abc|
+-------------------------+
Example 2: Using string_agg function with a delimiter
Python
from pyspark.sql import functions as sf
df = spark.createDataFrame([('a',), ('b',), (None,), ('c',)], ['strings'])
df.select(sf.string_agg('strings', ', ')).show()
Output
+-----------------------+
|string_agg(strings, , )|
+-----------------------+
| a, b, c|
+-----------------------+
Example 3: Using string_agg function with a binary column and delimiter
Python
from pyspark.sql import functions as sf
df = spark.createDataFrame([(b'\x01',), (b'\x02',), (None,), (b'\x03',)], ['bytes'])
df.select(sf.string_agg('bytes', b'\x42')).show()
Output
+------------------------+
|string_agg(bytes, X'42')|
+------------------------+
| [01 42 02 42 03]|
+------------------------+