CODEWITHSUNDEEP
scala
chiappone
chiappone

Reputation: 2908

Scala calculating two values in a map

I have the following map Map(FULL -> 3854.0, REMAINING -> 3769.0) I would like to compute the two values such that the (FULL/REMAINING)*100 Is there an good way to do this? I tried m.foldLeft(0)(_/_._2) but the compilier is complaining about a type mismatch between float and Int?

Upvotes: 0

Views: 92

Answers (2)

drexin
drexin

Reputation: 24403

With a Map, there is no guarantee, that the two value are really present. So you may want to create a class for that, as Ken Bloom already suggested, or do it with the get method of Map, which returns an Option[B]:

val resOpt = for {
  full <- m.get("FULL")
  remainig <- m.get("REMAINING")
} yield (full / remaining) * 100

resOpt.getOrElse(someDefaultValue)

This way you avoid nasty runtime errors.

Upvotes: 1

Ken Bloom
Ken Bloom

Reputation: 58790

You can fix the type mismatch by specifying 0.0 as the first argument to foldLeft, but that won't make your code right. It will then compute 0.0/3854.0/3769.0 which equals 0.0.

In fact, Map(FULL -> 3854.0, REMAINING -> 3769.0) is not guaranteed to be ordered, so I'm pretty sure the best you can do is m('FULL') / m('REMAINING').

Perhaps you want to create a case class for this instead, in which case you could just say m.full/m.remaining or even make a method to compute that automatically.

Upvotes: 4

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