What are these in scala

Question

Can you tell me what do these in scala : _* & @_* mean?

Answer 1

As is widely used, and has different meanings depending on the context so I'll explain it to you with an example. Here’s a sample:

import scala._ // Wild card -- all of Scala is imported
import scala.{ Predef => _, _ } // Exclusion, everything except Predef
def f[M[_]] // Higher kinded type parameter
def f(m: M[_]) // Existential type
_ + _ // Anonymous function placeholder parameter
m _ // Eta expansion of method into method value
m(_) // Partial function application
_ => 5 // Discarded parameter
case _ => // Wild card pattern -- matches anything
f(xs: _*) // Sequence xs is passed as multiple parameters to f(ys: T*)
case Seq(xs @ _*) // Identifier xs is bound to the whole matched sequence.

Hope this helps!

If you want to know more about Apache Spark Scala, It's highly recommended to go for Spark certification course today.

Thanks!!