如何在Java中表示2D矩阵？ [英] How to represent a 2D matrix in Java?

问题描述

我必须在Java中创建一个2D矩阵（由双重值组成）以及1D矢量。应该可以访问单个行和列以及各个元素。此外，它应该是线程安全的（线程同时写入）。也许后来我也需要一些矩阵运算。

哪种数据结构最适合？只是2D数组或TreeMap？还是有任何惊人的外部图书馆？

解决方案

您应该使用Vector为2D数组。 线程安全。

 向量<向量&Double>> matrix = new Vector< Vector&Double>>（）; （int i = 0; i <2; i ++）
 
 {
矢量< Double> r = new Vector<>（）; （int j = 0; j< 2; j ++）
 {
 r.add（Math.random（））; 
} 
 matrix.add（r）; （int i = 0; i< 2; i ++）{
} 
向量< Double> r = matrix.get（i）; （int j = 0; j< 2; j ++）{
 System.out.print（r.get（j））; 
 
} 
 System.out.println（）; 
} 
  

如果这是您的矩阵索引

00 01

10 11

您可以获得这样的特定索引值

  Double r2c1 = matrix.get（1）.get（0）; //第二行第一列
  

看看
矢量

I have to create in Java a 2D matrix (consisting of double values) as well as a 1D vector. It should be possible to access individual rows and columns as well as individual elements. Moreover, it should be thread-safe (threads writing at the same time). Perhaps later I need some matrix operations too.

Which data structure is best for this? Just a 2D array or a TreeMap? Or is there any amazing external library?

解决方案

You should use Vector for 2D array. It is threadsafe.

Vector<Vector<Double>>  matrix= new Vector<Vector<Double>>();

    for(int i=0;i<2;i++){
        Vector<Double> r=new Vector<>();
        for(int j=0;j<2;j++){
            r.add(Math.random());
        }
        matrix.add(r);
    }
    for(int i=0;i<2;i++){
        Vector<Double> r=matrix.get(i);
        for(int j=0;j<2;j++){
            System.out.print(r.get(j));
        }
        System.out.println();
    }

If this is your matrix indexes

00 01

10 11

You can get specifix index value like this

Double r2c1=matrix.get(1).get(0); //2nd row 1st column

Have a look at Vector

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