Scala Iterator (Iterator)

Scala Collections

A Scala Iterator (iterator) is not a collection; it is a method for accessing a collection.

The two basic operations of an iterator it are next and hasNext.

Calling it.next() returns the next element of the iterator and updates the state of the iterator.

Calling it.hasNext() is used to check if there are any more elements in the collection.

The simplest way to let the iterator it return all elements one by one is by using a while loop:

Example

object Test {
  def main(args: Array[String]) {
    val it = Iterator("Baidu", "Google", "tutorialpro", "Taobao")

    while (it.hasNext){
      println(it.next())
    }
  }
}

Executing the above code, the output will be:

$ scalac Test.scala 
$ scala Test
Baidu
Google
tutorialpro
Taobao

Finding Maximum and Minimum Elements

You can use the it.min and it.max methods to find the maximum and minimum elements from the iterator, as shown in the example below:

Example

object Test {
  def main(args: Array[String]) {
    val ita = Iterator(20,40,2,50,69, 90)
    val itb = Iterator(20,40,2,50,69, 90)

    println("The maximum element is: " + ita.max )
    println("The minimum element is: " + itb.min )
  }
}

Executing the above code, the output will be:

$ scalac Test.scala 
$ scala Test
The maximum element is: 90
The minimum element is: 2

Getting the Length of an Iterator

You can use the it.size or it.length methods to see the number of elements in the iterator. Here is an example:

Example

object Test {
  def main(args: Array[String]) {
    val ita = Iterator(20,40,2,50,69, 90)
    val itb = Iterator(20,40,2,50,69, 90)

    println("The value of ita.size: " + ita.size )
    println("The value of itb.length: " + itb.length )
  }
}

Executing the above code, the output will be:

$ scalac Test.scala 
$ scala Test
The value of ita.size: 6
The value of itb.length: 6

Common Methods of Scala Iterator

The following table lists the commonly used methods of Scala Iterator: