Program to convert Java list to an iterator in Scala
Last Updated :
17 Jan, 2023
A java list can be converted to an iterator in Scala by utilizing toIterator method of Java in Scala. Here, we need to import Scala’s JavaConversions object in order to make this conversions work else an error will occur. Now, lets see some examples and then discuss how it works in details. Example:1#
Scala
import scala.collection.JavaConversions. _
object GfG
{
def main(args : Array[String])
{
val list = new java.util.ArrayList[Int]()
list.add( 5 )
list.add( 6 )
val iter = list.toIterator
println(iter)
}
}
|
Output:
non-empty iterator
Time Complexity : O(1) because the only operation being performed is the creation of a new Java ArrayList and adding two elements to it, both of which are constant-time operations. The toIterator method also has a constant-time complexity because it simply returns an iterator over the elements of the list.
Space complexity : O(1) because the only variables being used are a few integers and references to the Java ArrayList and iterator, which are all constant in size regardless of the input size.
Therefore, a non-empty iterator is returned. Here, firstly a list is created where, the int elements are added to it utilizing add method. After that toIterator method is utilized in order to convert the stated list to an iterator.
Example:2#
Scala
import scala.collection.JavaConversions. _
object GfG
{
def main(args : Array[String])
{
val list = new java.util.ArrayList[Int]()
val iter = list.toIterator
println(iter)
}
}
|
Time Complexity : O(1) because the only operation being performed is the creation of a new Java ArrayList and the toIterator method, both of which are constant-time operations. The toIterator method also has a constant-time complexity because it simply returns an iterator over the elements of the list
Space Complexity : O(1) because the only variables being used are a reference to the Java ArrayList and iterator, which are both constant in size regardless of the input size.
It is same as above example but here an empty iterator is returned as here the stated list is empty.
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