CODEWITHSUNDEEP
scalavisibility
D4Niel
D4Niel

Reputation: 39

Scala - how to make val visible

I have this method 

def example(something):something {
  val c=List()
  if(){
    if(){
      val a=List()
    }
    else{
      val a=List()
    }
  }
  //here a or b are not declared
  c:::a
}

How to declare it and make it visible? I can not use var.

Upvotes: 1

Views: 562

Answers (3)

Nicolas
Nicolas

Reputation: 24769

In your particular case, you do not need the val a:

def example(something):something {
  val c= yourListC ::: if(firstTest){
                         if(secondTest){
                           yourListA
                         }
                         else{
                           yourOtherListA
                         }
                       } else {
                           anAdequateEmptyList
                       }
}

Upvotes: 2

Kevin Wright
Kevin Wright

Reputation: 49705

Almost Everything in Scala returns a value (the exception is for statements such as package declarations and imports)

if/else statements, pattern matches, etc. etc.

This means that your if/else block returns a value, and is especially keen to do so, very much like the ?: ternary operator in Java.

val foo = ... some integer ...
val bar = if(foo >= 0) "positive" else "negative"

Or using blocks:

val foo = ... some integer ...
val bar = if(foo >= 0) {
  "positive"
} else {
  "negative"
}

Nest 'em to your heart's content if you wish!

val foo2 = ... some other integer ...
val bar = if(foo >= 0) {
  if(foo2 >= 0) {
    "double positive"
  } else {
    "part-way there"
  }
} else {
  "foo was negative"
}

and even mix 'n' match styles:

println(
  if(foo >= 0) {
    if(foo2 >= 0) "double positive" else "part-way there"
  } else {
    "foo was negative"
  }
)

Upvotes: 6

Dmitry Stropalov
Dmitry Stropalov

Reputation: 790

You can't make it visible outside declaration scope, so, maybe, try this:

def example(somthing):somthing{    
  val c = { 

    if (something) {
      (0 to 10).toList
    } else {
      (0 to 5).toList
    }

  }
}

Upvotes: 6

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