Question

I have the function that could return null value:

def func(arg: AnyRef): String = {
...
}

and I want to add the result to list, if it is not null:

...
val l = func(o)
if (l != null)
  list :+= l
....

or

def func(arg: AnyRef): Option[String] = {
...
}

...
func(o).filter(_ != null).map(f => list :+= f)
...

But it looks too heavy.

Are there any better solutions?

Answer 1

You can simply append the option to the list. This is because an Option can be treated as an Iterable (empty forNone, with one single element forSome) thanks to the implicit conversion Option.option2Iterable.

So for the option variant (second version of func) just do:

list ++= func(o)

For the other variant (first version of func) you can first convert the return value of func to an Option using Option.apply (will turn null to None or else wrap the value with Some) and then do like above. Which gives:

list ++= Option(func(o))