Invoke a method using a tuple as the parameter lis

问题:

This question already has answers here:

scala tuple unpacking (5 answers)

Closed 4 years ago.

I wonder what is the best way to do this.

val foo = Some("a")
val bar = Some(2)

def baz(a: String, b: Int) = if((b % 2) == 0) Some(a+","+b) else None

(x zip y) flatMap baz //does not compile of course
(x zip y) flatMap { x => baz(x._1, x._2) } //ugly

I would presume that Odersky et al. have another trick up theirs sleeve to reduce the noise in this example.

So the question is how to fight the clutter here assuming you are not allowed to change the implementation of baz (e.g. def baz(a: (String Int))).

回答1:

This question has already been answered here: scala tuple unpacking

First, make foo to a function by partial application, then call tupled with your parameter list:

(foo _).tupled(myTuple)

回答2:

The most common way to cleanly unpack anything is with patterns or for-comprehensions:

for ((a,b) <- (x zip y); c <- baz(a,b)) yield(c)