you can use concat_ws
>>> from pyspark.sql.functions import col, concat_ws
>>> data_df.show()
+---+---------+---------+---+---+---------------+
| _1| _2| _3| _4| _5| _6|
+---+---------+---------+---+---+---------------+
| 1|[a, b, c]|[c, d, e]| 10| 20| [a, b]|
| 2|[d, f, h]| [s, c]| 11| 21|[f, g, h, j, k]|
| 3|[a, f, g]|[r, t, y]| 12| 22| [g, h]|
+---+---------+---------+---+---+---------------+
>>> df2 = data_df.withColumn("_2",concat_ws(",",col("_2"))).withColumn("_3",concat_ws(",",col("_3"))).withColumn("_6",concat_ws(",",col("_6")))
>>> df2.show()
+---+-----+-----+---+---+---------+
| _1| _2| _3| _4| _5| _6|
+---+-----+-----+---+---+---------+
| 1|a,b,c|c,d,e| 10| 20| a,b|
| 2|d,f,h| s,c| 11| 21|f,g,h,j,k|
| 3|a,f,g|r,t,y| 12| 22| g,h|
+---+-----+-----+---+---+---------+
>>> df2.printSchema()
root
|-- _1: long (nullable = true)
|-- _2: string (nullable = false)
|-- _3: string (nullable = false)
|-- _4: long (nullable = true)
|-- _5: long (nullable = true)
|-- _6: string (nullable = false)