Type parameters applied to Scala Function

Question

I am trying to understand the type parameters when applied to a function.

I would like to use Generic Types in the below method but using String and Int for my understa

Answer 1

It's good trying to make your own examples, but have you tried any examples from books, articles or tutorials? There's probably a good one in Scala for the Impatient by Cay Horstmann.

Here's a decent example from the Tour de Scala:

def listOfDuplicates[A](x: A, length: Int): List[A] = {
  if (length < 1)
    Nil
  else
    x :: listOfDuplicates(x, length - 1)
}

Sometimes you can omit the type parameter, but let's ignore that for now and declare the types explicitly:

listOfDuplicates[Int](43, 5) // Should give a list with 43 five times
listOfDuplicates[String]("Hello, world! ", 3) // "Hello, world!" thrice
listOfDuplicates[(Int, Int)]((0, 1), 8) // The pair (0, 1) eight times

This shows that A can be Int, String, (Int, Int) or just about anything else we can think of. Not sure you'd ever have a practical need for this, but you can even do something like this:

def wrapLength(str: String): Int = str.length

listOfDuplicates[String => Int](wrapLength(_), 2)

Here's a Scastie snippet in which you can play around with this.