How to declare empty list and then add string in scala?

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Scala lists are immutable by default. You cannot “add” an element, but you can form a new list by appending the new element in front. Since it is a new list, you need to reassign the reference (so you can’t use a val).

var dm  = List[String]()
var dk = List[Map[String,AnyRef]]()

.....

dm = "text" :: dm
dk = Map(1 -> "ok") :: dk

The operator :: creates the new list. You can also use the shorter syntax:

dm ::= "text" 
dk ::= Map(1 -> "ok")

NB: In scala don’t use the type Object but Any, AnyRef or AnyVal.

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