CODEWITHSUNDEEP
scala
Patrick Lafferty
Patrick Lafferty

Reputation: 557

Making a nested if statement more functional in scala

Just wondering if anyone would know how to make the following if statement more functional:

val value1 = 8
val value2 = 10


if(val1 > val2){
  println("\n" + stock1 + " has the highest current value")
}else if(val1 < val2){
  println("\n" + stock2 + " has the highest current value")
}else if(val1 == val2)){
  println("\nThe current value for " + stock1 + " is equal the current value for " + stock2)
}

I would be very grateful if someone could make a suggestion.

Thanks

Upvotes: 2

Views: 957

Answers (5)

longshorej
longshorej

Reputation: 381

I think the key thing about being functional here is to separate calculation from effects.

Your snippet is both calculating the message to print and doing IO. There's nothing wrong with using if statements -- in this case I'd say it's the clearest way to write it.

val value1 = 8
val value2 = 10

def valueMessage =
  if (val1 > val2) stock1 + " has the highest current value"
  else if (val1 < val2) stock2 + " has the highest current value"
  else "The current value for " + stock1 + " is equal the current value for " + stock2

def printValueMessage() = println("\n" + valueMessage)

printValueMessage() // unsafe

Upvotes: 4

Jasper-M
Jasper-M

Reputation: 15086

Like this? What do you think is not functional enough about your solution? 

println(
  if (val1 > val2)
    s"\n$stock1 has the highest current value"
  else if (val1 < val2)
    s"\n$stock2 has the highest current value"
  else 
    s"\nThe current value for $stock1 is equal the current value for $stock2"
)

Upvotes: 1

Peter Neyens
Peter Neyens

Reputation: 9820

Using cats-kernel you could use Order[Int].comparison :

import cats.kernel.Order
import cats.kernel.instances.int._
import cats.kernel.Comparison._

val message =
  Order[Int].comparison(val1, val2) match {
    case GreaterThan => s"$stock1 has the highest current value"
    case LessThan    => s"$stock2 has the highest current value"
    case EqualTo => 
      s"The current value for $stock1 is equal the current value for $stock2"
  }

println(s"\n$message")

Upvotes: 6

radumanolescu
radumanolescu

Reputation: 4161

Or this:

math.signum(value1 - value2) match {
      case -1 => println("v1 <= v2")
      case 1  => println("v1 >= v2")
      case _  => println("v1 == v2")
    }

Upvotes: 1

Andriy Kuba
Andriy Kuba

Reputation: 8263

match, if you like it

val1 match{
  case v if v > val2 => println("\n" + stock1 + " has the highest current value")
  case v if v < val2 => println("\n" + stock2 + " has the highest current value")
  case _ => println("\nThe current value for " + stock1 + " is equal the current value for " + stock2)
 }

Upvotes: 4

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