How to create an infinite collection from a Scala Set

Question

Is there a more elegant method than going through a Seq?

val origin = Set("a", "b")
val intermediate = origin.toSeq
val stream = Stream.from(0).map { index =>
    intermediate(index % intermediate.size)
}.toIterator

stream.next() // => "a"
stream.next() // => "b"
stream.next() // => "a"

I am specifically targeting Scala 2.9.

This may interest you : http://stackoverflow.com/questions/2097851/scala-repeat-a-finite-list-infinitely — Alexis C., Jul 20 '15 at 14:10
@AlexisC. why isn't this an answer? It's exactly what I was looking for! — François Beausoleil, Jul 20 '15 at 14:46

score 1 · Answer 1 · edited May 23 '17 at 12:21

1

This question is very similar to this one.

The easiest way is to use recursive definition:

val stream: Stream[String] = origin.toStream #::: stream

#::: is stream concatenation operator. It is equivalent to:

val stream: Stream[String] = origin.toStream.append(stream)

edited May 23 '17 at 12:21

Community

1
1

answered Jul 20 '15 at 14:50

krcz

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How to create an infinite collection from a Scala Set

1 Answers1