[create dataframe with schema] how-to create a dataframe obj with schema in scala spark #scala #spark #dataframe

create-dataframe-with-schema

          val spark = SparkSession.builder().getOrCreate()
          import spark.implicits._


          val df = spark
            .createDataFrame(
              spark.sparkContext.parallelize(
                Seq(
                  Row(
                    Map(("key1","val1") -> 1)
                  ),
                  Row(
                    Map(("key1","val2") -> 2)
                  )
                )),
              StructType(
                new StructType().add("server_rank_map", MapType(
                  new StructType()
                    .add("key_col", StringType , false)
                    .add("val_col" ,  StringType , false)
                  , IntegerType
                ) //eof MapType
                ) //eof add
              ) //eof schema
            ) //eof createDataFrame
        
          df.printSchema()