Java DoubleStream mapToObj()

DoubleStream mapToObj() 返回一个由应用给定函数的结果组成的对象值 Stream。

语法

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

参数： 该方法接受以下参数。

U: 新流的元素类型。stream： 一个支持顺序和平行聚合操作的元素序列。DoubleFunction : 代表一个接受双值参数并产生一个结果的函数。mapper : 一个适用于每个元素的无状态函数。

返回值： 该函数返回一个由应用给定函数的结果组成的 对象值Stream 。

下面的例子说明了mapToObj()方法。

例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);      }}

输出:

39.30399999999999591.125300.76300000000003704.969

例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)));    }}

输出:

13.414.516.718.9