IntStream mapToLong() in Java
IntStream mapToLong() returns a LongStream consisting of the results of applying the given function to the elements of this stream.
Note : IntStream mapToLong() is a intermediate operation. These operations are always lazy. Intermediate operations are invoked on a Stream instance and after they finish their processing, they give a Stream instance as output.
Syntax :
LongStream mapToLong(IntToLongFunction mapper)
Parameters :
- LongStream : A sequence of primitive long-valued elements. This is the long primitive specialization of Stream.
- mapper : A stateless function to apply to each element.
Return Value : The function returns a LongStream consisting of the results of applying the given function to the elements of this stream.
Example 1 :
// Java code for LongStream mapToLong // (IntToLongFunction mapper) import java.util.*; import java.util.stream.IntStream; import java.util.stream.LongStream; class GFG { // Driver code public static void main(String[] args) { // Creating an IntStream IntStream stream = IntStream.of( 2 , 4 , 6 , 8 , 10 ); // Using LongStream mapToLong(IntToLongFunction mapper) // to return a LongStream consisting of the // results of applying the given function to // the elements of this stream. LongStream stream1 = stream.mapToLong(num -> ( long )num); // Displaying the elements in stream1 stream1.forEach(System.out::println); } } |
Output :
2 4 6 8 10
Example 2 :
// Java code for LongStream mapToLong // (IntToLongFunction mapper) import java.util.*; import java.util.stream.IntStream; import java.util.stream.LongStream; class GFG { // Driver code public static void main(String[] args) { // Creating an IntStream IntStream stream = IntStream.of( 2 , 4 , 6 , 8 , 10 ); // Using LongStream mapToLong(IntToLongFunction mapper) // to return a LongStream consisting of the // results of applying the given function to // the elements of this stream. LongStream stream1 = stream.mapToLong(num -> ( long )num + Integer.MAX_VALUE); // Displaying the elements in stream1 stream1.forEach(System.out::println); } } |
Output :
2147483649 2147483651 2147483653 2147483655 2147483657
Example 3 :
// Java code for LongStream mapToLong // (IntToLongFunction mapper) import java.util.*; import java.util.stream.IntStream; import java.util.stream.LongStream; class GFG { // Driver code public static void main(String[] args) { // Creating an IntStream IntStream stream = IntStream.range( 5 , 10 ); // Using LongStream mapToLong(IntToLongFunction mapper) // to return a LongStream consisting of the // results of applying the given function to // the elements of this stream. LongStream stream1 = stream.mapToLong(num -> ( long )num - 20 ); // Displaying the elements in stream1 stream1.forEach(System.out::println); } } |
Output :
-15 -14 -13 -12 -11