如何在Java中减去两个列表/数组的值?

问题描述：

我正在研究Java项目，但遇到了问题.我想在列表/数组c中减去两个列表或数组a和b，但是我不知道该怎么做.我希望"a [i] -b [i]"应该在下一个列表c中，对于5-2 = 3，其值应为c[i]类似，任何建议和帮助将不胜感激.

I am working on a Java project and I am having a problem. I want to have the subtract of two lists or arrays a and b in list/array c but I don't know how to do that. I want "a[i] -b[i]" should be in next list c where the value should be c[i] similarly for 5-2=3 any suggestion and help would be appreciated.

代码:

public static void länge() {
    {
        BufferedReader br = null;
        try {
            br = new BufferedReader(new FileReader(new File("C:\\Users/Voodoothechild/Desktop/Pidata/Anfang.txt")));
            String line = null;
            while ((line = br.readLine()) != null) {         
                {
                    BufferedReader bro = null;
                    try {
                        bro = new BufferedReader(new FileReader(new File("C:\\Users/Voodoothechild/Desktop/Pidata/Ende.txt")));

                        String lines = null;
                        while ((lines = br.readLine()) != null) {

                            String[] anfang = line.split("\n");
                            String[] ende = lines.split("\n");

                            List<Integer> an = new ArrayList<Integer>();
                            List<Integer> en = new ArrayList<Integer>();

                            for (int index = 0 ; index<ende.length ; index++) {

                                an.add(Integer.parseInt(anfang[index]));
                                en.add(Integer.parseInt(ende[index]));
                                Integer[] anf = new Integer[an.size()];

                                int[] result = new int[anf.length]; 

                                for (int i = 0; i < result.length; i++) { 
                                    result[i] = anf[i] - end[i]; 
                                } 

                            } 
                        }    
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    } finally {
                        if (bro != null) {
                            try {
                                bro.close();
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }
            }
        } catch(FileNotFoundException e) {
            e.printStackTrace();
        } catch(IOException e) {
            e.printStackTrace();
        } finally {
            if (br != null) {
                try {
                    br.close();
                } catch(IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

答

使用Stream API可以轻松完成:

It can be done easily using Stream API:

int[] list1 = {4,2,1};
int[] list2 = {2,2,-1};

IntStream.range(0, list1.length)
  .mapToObj(i -> list1[i] - list2[i])
  .collect(Collectors.toList());

或者甚至更容易使用Javaslang:

or even easier using Javaslang:

Stream.range(0, list1.length)
  map(i -> list1[i] - list2[i]);

或将两个列表压缩在一起:

or by zipping two lists together:

List.ofAll(list1)
  .zip(List.ofAll(list2))
  .map(t -> t._1 - t._2);

如何在Java中减去两个列表/数组的值?

相关推荐