Convert the value in an Option to another type

Question

I'm trying to do something that seems like it should have a straight forward syntax/function in scala. I just don't know what that is. I'm trying to convert the contained value of an Option (if it is not None) to another type.

Simply I want to know what the code would be if I wanted to implement the following function

def myFunc(inVal:Option[Double]):Option[BigDecimal] = {
    //Code I need goes here
}

Note: I am not actually implementing this function, it just is the clearest way for me to demonstrate what I need

Answer 1

def myFunc(inVal: Option[Double]): Option[BigDecimal] =
  inVal map {d => d: BigDecimal}

In general if you want to transform value in container (Option, Seq, List, Try, Future, etc) you should use method map on this container.

Method map accepts lambda (function) as parameter and applies this function to all elements. map should not change the count of elements: map on Some will never return None.

You could use method BigDecimal.apply to convert Double to BigDecimal like this:

BigDecimal(1.1)
// res0: scala.math.BigDecimal = 1.1

But there is also an implicit conversion from Double to BigDecimal, so you could just specify desired type like this:

1.1: BigDecimal
// res0: scala.math.BigDecimal = 1.1

val bd: BigDecimal = 1.2

PS: type inference allows you to use d => d instead of d => d: BigDecimal here, but it will make your code very unclear.