scala - Spark : How to union all dataframe in loop

Question

Is there a way to get the dataframe that union dataframe in loop?

This is a sample code:

var fruits = List(
  \"apple\"
  ,\"orange\"
  ,\"melon\"
)          


        

Answer 1

You could created a sequence of DataFrames and then use reduce:

val results = fruits.
  map(fruit => Seq(("aaa", "bbb", fruit)).toDF("aCol","bCol","name")).
  reduce(_.union(_))

results.show()