Add an example for converting a map to a struct.

pyspark_cookbook.org

@@ -1321,6 +1321,33 @@ root
 |[1, 2, 5]|[1, 3]| [1, 3]|
 |[4, 4, 6]|[0, 2]| [0, 2]|
 
+** To convert a map to a struct
+#+BEGIN_SRC python :post pretty2orgtbl(data=*this*)
+  from pyspark.sql import SparkSession
+  import pyspark.sql.functions as F
+  spark = SparkSession.builder.master("local").appName("test-app").getOrCreate()
+  df = spark.sql("SELECT map('John', 1, 'Michael', 2) as Students_map")
+  df = df.withColumn("Students_struct", F.map_entries("Students_map").alias("a", "b"))
+  df.printSchema()
+  df.show(truncate=False)
+#+END_SRC
+
+#+RESULTS:
+:results:
+root
+ |-- Students_map: map (nullable = false)
+ |    |-- key: string
+ |    |-- value: integer (valueContainsNull = false)
+ |-- Students_struct: array (nullable = false)
+ |    |-- element: struct (containsNull = false)
+ |    |    |-- key: string (nullable = false)
+ |    |    |-- value: integer (nullable = false)
+
+| Students_map              | Students_struct           |
+|---------------------------+---------------------------|
+| {John -> 1, Michael -> 2} | [{John, 1}, {Michael, 2}] |
+:end:
+
 ** To slice an array
 #+BEGIN_SRC python :post pretty2orgtbl(data=*this*)
   import pyspark.sql.functions as F