- Scala Collections Tutorial
- Scala Collections - Home
- Scala Collections - Overview
- Scala Collections - Environment Setup
- Scala Collections - Arrays
- Scala Collections - Array
- Scala Collections - Multi-Dimensional Array
- Scala Collections - Array using Range
- Scala Collections - ArrayBuffer
- Scala Collections - Lists
- Scala Collections - List
- Scala Collections - ListBuffer
- Scala Collections - ListSet
- Scala Collections - Vector
- Scala Collections - Sets
- Scala Collections - Set
- Scala Collections - BitSet
- Scala Collections - HashSet
- Scala Collections - TreeSet
- Scala Collections - Maps
- Scala Collections - Map
- Scala Collections - HashMap
- Scala Collections - ListMap
- Scala Collections - Miscellaneous
- Scala Collections - Iterator
- Scala Collections - Option
- Scala Collections - Queue
- Scala Collections - Tuple
- Scala Collections - Seq
- Scala Collections - Stack
- Scala Collections - Stream
- Scala Collections Combinator methods
- Scala Collections - drop
- Scala Collections - dropWhile
- Scala Collections - filter
- Scala Collections - find
- Scala Collections - flatMap
- Scala Collections - flatten
- Scala Collections - fold
- Scala Collections - foldLeft
- Scala Collections - foldRight
- Scala Collections - map
- Scala Collections - partition
- Scala Collections - reduce
- Scala Collections - scan
- Scala Collections - zip
- Scala Collections Useful Resources
- Scala Collections - Quick Guide
- Scala Collections - Useful Resources
- Scala Collections - Discussion
Scala Collections - Stream
Scala Stream is special list with lazy evaluation feature. In scala stream, elements are evaluated only when they are needed. Stream supports lazy computation and is performance savvy.
Declaring Stream Variables
The following is the syntax for declaring an Stream variable.
Syntax
val stream = 1 #:: 2 #:: 3 #:: Stream.empty
Here, stream is declared as a stream of numbers. Here 1 is head of stream, 2, 3 are tail of stream. Stream.empty marks the end of the stream. Values can be retrived using take commands like the following −
Command
stream.take(2)
Processing Stream
Below is an example program of showing how to create, initialize and process Stream −
Example
import scala.collection.immutable.Stream
object Demo {
def main(args: Array[String]) = {
val stream = 1 #:: 2 #:: 3 #:: Stream.empty
// print stream
println(stream)
// Print first two elements
stream.take(2).print
println()
// Create an empty stream
val stream1: Stream[Int] = Stream.empty[Int]
// Print element
println(s"Stream: $stream1")
}
}
Save the above program in Demo.scala. The following commands are used to compile and execute this program.
Command
\>scalac Demo.scala \>scala Demo
Output
Stream(1, <not computed>) 1, 2 Stream: Stream()
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