Upacking a list to select multiple columns from a spark data frame

Question

I have a spark data frame df. Is there a way of sub selecting a few columns using a list of these columns?

scala> df.columns
res0: Array[Stri         


        

Answer 1

You can pass arguments of type Column* to select:

val df = spark.read.json("example.json")
val cols: List[String] = List("a", "b")
//convert string to Column
val col: List[Column] = cols.map(df(_))
df.select(col:_*)