DoubleStream mapToLong() in Java
DoubleStream mapToLong() returns a LongStream consisting of the results of applying the given function to the elements of this stream.
Note : DoubleStream 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(DoubleToLongFunction mapper)
Parameters :
- DoubleStream : A sequence of primitive double-valued elements. This is the double 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 :
import java.util.*;
import java.util.stream.LongStream;
import java.util.stream.DoubleStream;
class GFG {
public static void main(String[] args)
{
DoubleStream stream = DoubleStream.of( 3.3 , 6.5 , 16.4 ,
8.7 , 10.4 );
LongStream stream1 = stream.mapToLong(num -> ( long )num);
stream1.forEach(System.out::println);
}
}
|
Output :
3
6
16
8
10
Example 2 :
import java.util.*;
import java.util.stream.LongStream;
import java.util.stream.DoubleStream;
class GFG {
public static void main(String[] args)
{
DoubleStream stream = DoubleStream.of( 3.3 , 6.5 , 16.4 ,
8.7 , 10.4 );
LongStream stream1 = stream.mapToLong(num -> ( long )num - 10 );
stream1.forEach(System.out::println);
}
}
|
Output :
-7
-4
6
-2
0
Example 3 :
import java.util.*;
import java.util.stream.LongStream;
import java.util.stream.DoubleStream;
class GFG {
public static void main(String[] args)
{
DoubleStream stream = DoubleStream.of( 3.3 , 6.5 , 16.4 ,
8.7 , 10.4 );
LongStream stream1 = stream.mapToLong(num -> ( long )( 2 * num * num));
stream1.forEach(System.out::println);
}
}
|
Output :
21
84
537
151
216
Last Updated :
06 Dec, 2018
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