CODEWITHSUNDEEP
scala
IntrestedInSpark
IntrestedInSpark

Reputation: 115

How return works in scala on specific example?

let's consider:

def foo: Int = { 
  val sumR: List[Int] => Int = _.foldLeft(0)((n, m) => return n + m)
  sumR(List(1,2,3)) + sumR(List(4,5,6))
}

scala> foo
res4: Int = 1

Why first part of sumR(List(1,2,3)) + sumR(List(4,5,6)) expression is treated better? After all, return should lead to returning from sumR. So, why the result is not equal to 1+4?

Upvotes: 1

Views: 65

Answers (1)

mck
mck

Reputation: 42342

The return is related to the foo method rather than the sumR function, so return causes the foo method to stop at that point and returns 1 because it's the first iteration in the foldLeft operation. The second sumR is not computed.

If you want 5 as the result, you should define sumR as a method rather than an anonymous function, so that return causes the sumR method to stop, rather than the foo method to stop.

def foo: Int = { 
  def sumR(l: List[Int]): Int = l.foldLeft(0)((n, m) => return n + m)
  sumR(List(1,2,3)) + sumR(List(4,5,6))
}

foo
// Int = 5

Upvotes: 5

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