In Scala, List is Immutable But -

i beginner scala language. in scala, list immutable per below code:

scala> var list = list(1,2,3,4,5)    // list created named ‘ list ’                                             list: list[int] = list(1, 2, 3, 4, 5)                                             scala> 25 :: list // prepend cons( :: ) , here new list created.                                                         res2: list[int] = list(25, 1, 2, 3, 4, 5)  scala> list                        // print ‘  list ’    res3: list[int] = list(1, 2, 3, 4, 5) 

but,

scala> list                                                                      res1: list[int] = list(1, 2, 3, 4, 5)                                             scala> list :+= 12     // append list :+=  scala> list                                                                      res2: list[int] = list(1, 2, 3, 4, 5, 12) 

in above example, same "list" appended. how list immutable? it's confusing me. 1 kindly explain me?

http://daily-scala.blogspot.co.uk/2010/03/implicit-operator.html

:+= not appending, it's appending new list , reassigning variable point new list. it's equivalent list = list + 12.

25 ++ list making new list, not assigning anywhere.