How do I rewrite this conditional with an option in Scala in a cleaner way?

Question

Is there a cleaner way of writing this in scala?

def myFunction(somethingA: String, somethingB: Option[String]): Unit =
  if (somethingB.isDefined) 
    foo("somethingA" -> somethingA, "somethingB" -> somethingB.get) 
  else
    foo("somethingA" -> somethingA)

I was thinking something along the lines of:

def myFunction(somethingA: String, somethingB: Option[String]): Unit =
  foo("somethingA" -> somethingA, somethingB.map("somethingB" -> _).getOrElse(.... pleh ....))

But even if I replace the ".... pleh ...." part with some kind of expression, i don't want it to even add the mapping if somethingB isn't defined. So I don't envision that remotely working. Not sure what the right solution is.

score 2 · Accepted Answer · answered Jun 25 '13 at 23:52

2

Not much cleaner:

def myFunction(somethingA: String, somethingB: Option[String]): Unit = somethingB match {
  case Some(b) => foo("somethingA" -> somethingA, "somethingB" -> b)
  case None    => foo("somethingA" -> somethingA)
}

answered Jun 25 '13 at 23:52

om-nom-nom

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That's what I was thinking. Was trying to envisage some sort of `flatMap` based option but couldn't quite work it out. +1 – Boris the Spider Jun 26 '13 at 00:08
Yeah that's about as clean as it gets I guess. Thanks – Donuts Jun 26 '13 at 17:27

score 2 · Answer 2 · answered Jun 26 '13 at 01:22

You don't say what foo is, but given

scala> def foo(ps: (String, String)*) = ps.size
foo: (ps: (String, String)*)Int

then

scala> def myFunction(somethingA: String, somethingB: Option[String]): Int =
     | foo(List(Some("A"->somethingA), somethingB.map("B"->_)).flatten: _*)
myFunction: (somethingA: String, somethingB: Option[String])Int

may be what you intend.

score 1 · Answer 3 · answered Jun 26 '13 at 00:21

1

You could also try folding the Option if you are using Scala 2.10:

val result = somethingB.fold(foo("somethingA" -> somethingA))(b => foo("somethingA" -> somethingA, "somethingB" -> b))

answered Jun 26 '13 at 00:21

cmbaxter

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score 0 · Answer 4 · answered Jun 26 '13 at 00:05

0

My 2 cents:

val a = "somethingA" -> somethingA

somethingB.map{ b =>
   foo(a, "somethingB" -> b) 
}.getOrElse { foo(a) }

Hardly more readable. Btw. I don't think you can change the call binding depending on a value :(

answered Jun 26 '13 at 00:05

gzm0

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How do I rewrite this conditional with an option in Scala in a cleaner way?

4 Answers4