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Java DoubleStream mapToInt()用法及代码示例


DoubleStream mapToInt()返回一个IntStream,其中包括将给定函数应用于此流的元素的结果。

注意:DoubleStream mapToInt()是中间操作。这些操作总是很懒。在Stream实例上调用中间操作,并在完成处理后将中间实例作为输出提供。
用法:

IntStream mapToInt(DoubleToIntFunction mapper)

参数:


  1. IntStream : 原始整数值元素的序列。这是Stream的int原语专业化。
  2. mapper : 适用于每个元素的无状态函数。

返回值:该函数返回一个IntStream,其中包括将给定函数应用于此流的元素的结果。

示例1:

// Java code for IntStream mapToInt 
// (DoubleToIntFunction mapper) 
import java.util.*; 
import java.util.stream.IntStream; 
import java.util.stream.DoubleStream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
        // Creating a DoubleStream 
        DoubleStream stream = DoubleStream.of(2.3, 4.5, 6.4, 
                                              8.7, 10.4); 
  
        // Using IntStream mapToInt(DoubleToIntFunction mapper) 
        // to return an IntStream consisting of the 
        // results of applying the given function to 
        // the elements of this stream. 
        IntStream stream1 = stream.mapToInt(num -> (int)num); 
  
        // Displaying the elements in stream1 
        stream1.forEach(System.out::println); 
    } 
}

输出:

2
4
6
8
10

示例2:

// Java code for IntStream mapToInt 
// (DoubleToIntFunction mapper) 
import java.util.*; 
import java.util.stream.IntStream; 
import java.util.stream.DoubleStream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
        // Creating a DoubleStream 
        DoubleStream stream = DoubleStream.of(2.3, 4.5, 6.4, 
                                              8.7, 10.4); 
  
        // Using IntStream mapToInt(DoubleToIntFunction mapper) 
        // to return an IntStream consisting of the 
        // results of applying the given function to 
        // the elements of this stream. 
        IntStream stream1 = stream.mapToInt(num -> (int)num - 10000); 
  
        // Displaying the elements in stream1 
        stream1.forEach(System.out::println); 
    } 
}

输出:

-9998
-9996
-9994
-9992
-9990

示例3:

// Java code for IntStream mapToInt 
// (DoubleToIntFunction mapper) 
import java.util.*; 
import java.util.stream.IntStream; 
import java.util.stream.DoubleStream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
        // Creating a DoubleStream 
        DoubleStream stream = DoubleStream.of(1.3, 2.4, 3.4, 
                                              4.5, 5.7); 
  
        // Using IntStream mapToInt(DoubleToIntFunction mapper) 
        // to return an IntStream consisting of the 
        // results of applying the given function to 
        // the elements of this stream. 
        IntStream stream1 = stream.mapToInt(num -> (int)(num * num * num)); 
  
        // Displaying the elements in stream1 
        stream1.forEach(System.out::println); 
    } 
}

输出:

2
13
39
91
185


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注:本文由纯净天空筛选整理自Sahil_Bansall大神的英文原创作品 DoubleStream mapToInt() in Java。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。