CODEWITHSUNDEEP
scala
blue-sky
blue-sky

Reputation: 53786

Use of _ when invoking a method

Output of below : 

getNum(_);
  getNum(3);

  def getNum(num: Int) {
    println("Num is " + num)
  }

is 

Num is 3

Why is getNum(_); not invoked ? How is _ used in this case ?

Upvotes: 0

Views: 44

Answers (2)

pedrofurla
pedrofurla

Reputation: 12783

What you'd expect it to be? getNum(null) ?

The getNum(_); is translated into, something like:

{ x:Int => getNum(x) }

Which is a anonymous function and a value itself.

You could do for example:

val f = getNum(_)
f(42)

Then you'd see:

Num is 42

Upvotes: 6

JimN
JimN

Reputation: 3150

_ is used to partially apply a function. Partial application of a function produces another function with some of its parameters already applied.

val f = getNum(_) // partially apply
f(3) // apply the function

Upvotes: 1

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