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java - 将多维数组保存到文本文件中添加额外的列

问题描述

我有一个任务需要我将一个带有double值的数组传递到 Java 中的文本文件中。我用于BufferedWriter此任务，但问题是我在文本文件中获得了零值的额外列。

例如，如果我尝试将以下数据写入文本文件：

1.0, 2.0, 3.0
2.0, 1.0, 1.0
3.0, 2.0, 2.0

我得到以下结果：

1.0,2.0,3.0
2.0,1.0,1.0
3.0,2.0,2.0
0.0,0.0,0.0
0.0,0.0,0.0
0.0,0.0,0.0
0.0,0.0,0.0
0.0,0.0,0.0
0.0,0.0,0.0
0.0,0.0,0.0
0.0,0.0,0.0
0.0,0.0,0.0
0.0,0.0,0.0

这是我使用的代码：

ArrayList<String> list = new ArrayList<String>();
    File file1 = new File("file.txt"); 
        Scanner sc  = null;    
        sc = new Scanner( file1);        
        String  line = "";
        int maxLen = 0;
        while(sc.hasNextLine()){
            line = sc.nextLine();
            list.add(line);
            if(line.length() > maxLen)
                maxLen = line.length(); 
        }
        System.out.println(list); 
        int rows = maxLen;
        int col = list.size();
        double arr[][] = new double[rows][col];
        rows = 0; 
        for(int i=0;i<col;i++)
        {
            String s = list.get(i); 
            String []values = s.split(", "); 
            if(rows < values.length)
                rows = values.length; 
            for(int j=0;j<values.length;j++)
            {
                if (!values[j].isEmpty()) {
                arr[j][i] = Double.parseDouble(values[j]);

                }
                }
        }
        for(int i=0;i<rows;i++)
        {
            for(int j=0;j<col;j++)
            {
                System.out.print(arr[i][j]+", ");// displaying numbers

            }
            System.out.println();

        }

File filename = new File("FinalTopFeatures1.txt");
BufferedWriter bw = new BufferedWriter(new FileWriter(filename));

for (int i = 0; i < arr.length; i++) {
   for (int j = 0; j < arr[i].length; j++) {
      bw.write(arr[i][j] + ((j == arr[i].length-1) ? "" : ","));
   }
   bw.newLine();
}
bw.close();

标签： javamatrixtext-files

解决方案

检查数组的长度 ( arr.length)。它正在写入包含零值的整个数组。如果您不想写入所有零值，那么：您可以减小 arr 大小或仅针对包含数据的行数迭代 for 循环。假设您的情况只有 3 行包含数据。所以：

for (int i = 0; i < rows; i++) {
   for (int j = 0; j < col; j++) {
      bw.write(arr[i][j] + ((j == col-1) ? "" : ","));
   }
   bw.newLine();
}

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