How to create an immutable array within a mutable array in scala?-CodePudding

So I am trying to create an immutable array of size 10 within a mutable array in scala. In this immutable array I want to store key, value pairs. so far I have this mutable array:

val array1 = mutable.ArrayBuffer[Option[IndexedSeq[(A,B)]]]()

Now to create an immutable buffer in array1 would I just do:

array1(0) = immutable.ArrayBuffer[](10)

I am confused on what would go within the brackets of the immutable buffer for the type.

CodePudding user response：

There is no immutable.ArrayBuffer. ArrayBuffer is mutable.

Trait IndexedSeq can correspond to both immutable and mutable collections, so you have options what to use as your inner elements:

type A = Int
type B = Int

val array1 = mutable.ArrayBuffer[Option[IndexedSeq[(A,B)]]]()

// Adds immutable Vector
array1  = Some(IndexedSeq[(A, B)]( (1,2), (3,4) ))

// Adds mutable ArrayBuffer
array1  = Some(ArrayBuffer[(A, B)]( (1,2), (3,4) ))

Note, since your inner element is Option[IndexedSeq[...]], you need to wrap the elements you are adding in Some.