PySpark DataFrame - explode Array and Map Columns

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In PySpark, we can use explode function to explode an array or a map column. After exploding, the DataFrame will end up with more rows. 

Code snippet

The following code snippet explode an array column.

from pyspark.sql import SparkSession
import pyspark.sql.functions as F

appName = "PySpark DataFrame - explode function"
master = "local"

# Create Spark session
spark = SparkSession.builder \
    .appName(appName) \
    .master(master) \
    .getOrCreate()

spark.sparkContext.setLogLevel('WARN')

data = [{"values": [1, 2, 3, 4, 5]}, {"values": [6, 7, 8]}]

df = spark.createDataFrame(data)
df.show()

df.withColumn('value', F.explode(df['values'])).show()

Each value of the array becomes a column in a row:

+---------------+-----+
|         values|value|
+---------------+-----+
|[1, 2, 3, 4, 5]|    1|
|[1, 2, 3, 4, 5]|    2|
|[1, 2, 3, 4, 5]|    3|
|[1, 2, 3, 4, 5]|    4|
|[1, 2, 3, 4, 5]|    5|
|      [6, 7, 8]|    6|
|      [6, 7, 8]|    7|
|      [6, 7, 8]|    8|
+---------------+-----+

For map column, we can also use explode function. 

from pyspark.sql import SparkSession
import pyspark.sql.functions as F

appName = "PySpark DataFrame - explode function"
master = "local"

# Create Spark session
spark = SparkSession.builder \
    .appName(appName) \
    .master(master) \
    .getOrCreate()

spark.sparkContext.setLogLevel('WARN')

data = [{"values": {"a": "100", "b": "200"}},
        {"values": {"a": "1000", "b": "2000"}}]

df = spark.createDataFrame(data)
df.show()

df = df.select("*", F.explode(df['values']).alias('key', 'value'))
df.show()
The output includes one row for each attribute in each map object as the following shows:
+--------------------+
|              values|
+--------------------+
|[a -> 100, b -> 200]|
|[a -> 1000, b -> ...|
+--------------------+

+--------------------+---+-----+
|              values|key|value|
+--------------------+---+-----+
|[a -> 100, b -> 200]|  a|  100|
|[a -> 100, b -> 200]|  b|  200|
|[a -> 1000, b -> ...|  a| 1000|
|[a -> 1000, b -> ...|  b| 2000|
+--------------------+---+-----+
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