Question

val total_breaks = //a random number

total_breaks match {
  case i if(i < 0) => chartTemplate.setAttribute("totalBreaks", 0)
  case _ => chartTemplate.setAttribute("totalBreaks", total_breaks)
}

I was thinking there was a function in Scala that could shorten this. I thought min did this but I guess not. I can’t seem to find documentation on min, max, etc.

Something like total_breaks.min(0). Display 0 if under 0 if not display total_breaks.

Also is there a way do something like this

(4 + 5) match {
  case 0 => println("test")
  case _ => println(_) //i need to display the number passed into match?  Is this not  possible?
}

If I do case i => println(i) is that the same as case _ => ? Is that the fallback?

Answer 1

There are methods min and max defined in GenTraversableOnce, and thus available on sequences. You can use them as:

scala> List(1, -4, 0).min
resN: -4

There is also min and max defined in RichInt, that work like operators on anything that can be converted to RichInt, typically your vanilla integers:

scala> -4 min 0
resN: -4

So if you want something that returns your number, say x if x is greater than 0 and 0 otherwise, you can write:

scala> x max 0

That means you can rewrite your pattern-matching as:

chartTemplate.setAttribute("totalBreaks", total_breaks max 0)

For your second question, _ and i are both valid patterns that will match anything. The difference is that in the first case you do not bind what you have matched to a variable. Using println(_) is wrong, though; as such, it corresponds to an anonymous function that prints its first argument. So if you don’t want to repeat the expression (4 + 5), you should indeed write your pattern and code as:

case i => println(i)