Simple scala question. Consider the below.
scala> var mycounter: Int = 0; mycounter: Int = 0 scala> mycounter += 1 scala> mycounter res1: Int = 1 In the second statement I increment my counter. But nothing is returned. How do I increment and return something in one statement.
Using '+=' return Unit, so you should do:
{ mycounter += 1; mycounter } You can too do the trick using a closure (as function parameters are val):
scala> var x = 1 x: Int = 1 scala> def f(y: Int) = { x += y; x} f: (y: Int)Int scala> f(1) res5: Int = 2 scala> f(5) res6: Int = 7 scala> x res7: Int = 7 BTW, you might consider using an immutable value instead, and embrace this programming style, then all your statements will return something ;)
Sometimes I do this:
val nextId = { var i = 0; () => { i += 1; i} } println(nextId()) //> 1 println(nextId()) //> 2 Might not work for you if you need sometime to access the value without incrementing.
Assignment is an expression that is evaluated to Unit. Reasoning behind it can be found here: What is the motivation for Scala assignment evaluating to Unit rather than the value assigned?
In Scala this is usually not a problem because there probably is a different construct for the problem you are solving.
I don't know your exact use case, but if you want to use the incrementation it might be in the following form:
(1 to 10).foreach { i => // do something with i } 
var. In that case you might create a method as Alois Cochard suggested: def increment:Int = { counter += 1; counter }
Unit.