DoubleStream mapToObj() in Java

DoubleStream mapToObj() returns an object-valued Stream consisting of the results of applying the given function.

Syntax:

<U> Stream<U> 
mapToObj(DoubleFunction<? 
extends U> mapper)

Parameters: This method accepts following parameters:

1. U: The element type of the new stream.
2. Stream : A sequence of elements supporting sequential and parallel aggregate operations.
3. DoubleFunction : Represents a function that accepts an double-valued argument and produces a result.
4. mapper : A stateless function to apply to each element.

Return Value: The function returns an object-valued Stream consisting of the results of applying the given function.

Below examples illustrate the mapToObj() method:

Example 1 :

// Java code for DoubleStream mapToObj
// (DoubleFunction mapper)

import java.util.*;
import java.util.stream.Stream;
import java.util.stream.DoubleStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {
        // Creating a DoubleStream
        DoubleStream stream = DoubleStream.of(3.4, 4.5,
                                              6.7, 8.9);

        // Using DoubleStream mapToObj(DoubleFunction mapper)
        // and displaying an object-valued Stream
        // consisting of the results of
        // applying the given function
        stream.mapToObj(num ->{return num * num * num ;})
                           .forEach(System.out::println);

    }
}

Output:

39.303999999999995
91.125
300.76300000000003
704.969

Example 2 :

// Java code for DoubleStream mapToObj
// (DoubleFunction mapper)

import java.util.*;
import java.math.BigDecimal;
import java.util.stream.Stream;
import java.util.stream.DoubleStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {
        // Creating a DoubleStream
        DoubleStream stream = DoubleStream.of(3.4, 4.5,
                                              6.7, 8.9);

        // Creating a Stream
        // Using DoubleStream mapToObj(DoubleFunction mapper)
        Stream<BigDecimal> stream1 = stream
            .mapToObj(BigDecimal::valueOf);

        // Displaying an object-valued Stream
        // consisting of the results of
        // applying the given function.
        stream1.forEach(num -> System.out.println
                    (num.add(BigDecimal.TEN)));
    }
}

Output:

13.4
14.5
16.7
18.9