Scala encourages developers to create data structures that cannot be modified.
To create an immutable list:
val fruits = List("apple", "pear", "orange")
Concatenate two lists:
val summerFruits = List("banana", "orange")
val winterFruits = List("strawberry", "apple", "pear")
val fruits = summerFruits :: winterFruits
// fruits is now List("banana", "orange", "strawberry", "apple", "pear")
If you do need to be able to modify a list, you can create a mutable list like this:
val seasonFruits = scala.collection.mutable.ListBuffer("banana", "orange")
if(month > 3 && month < 9) { // We're in Argentina, not the USA :)
seasonFruits(0) = "strawberry"
seasonFruits(1) = "pear"
}