how to get Dataframe from list spark scala - scala

Question

I have a list of RDD. I have iterated the rdd and for each elemet of rdd I am doing some parsing logic. Finally I getting
val mRdd = nRdd.map {
ele => //parsing logic, I have the below field
colum = Array[String] // example ['id','name','dept']<br>
c_type = Array[String] // example ['Int','String','String']<br>
value = ArrayBuffer[String] // [1,lucy,it][2,denis,cs]<br>
}
How I can get the list of dataframe in mRdd
I tried a logic to create dataframe, in this case I have to rdd first. But I can't create rdd inside rdd.
I am new in spark. I am using spark 1.6.3
Please help me

Answer 1

In order to convert an RDD into a Dataframe, you would need to do the following:
Approach 1 - Use createDaframe function:
val mRdd: Seq[DataFrame] = nRdd.map {ele =>
val parsedRDD = ele //apply parse logic here
val schema = StructType(Seq(
StructField("id", IntegerType),
StructField("name", StringType),
StructField("dept", StringType)
))
createDataframe(parsedRDD, schema)
}
Read more about this approach here: https://spark.apache.org/docs/latest/sql-programming-guide.html#programmatically-specifying-the-schema
Approach 2 - Use toDF implicit function:
import sqlContext.implicits._
val mRdd: Seq[DataFrame] = nRdd.map {ele =>
val parsedRDD = ele //apply parse logic here
val columns = Seq("id", "name", "dept")
parsedRDD.toDF(columns: _*)
}