如何将文本文件转换为多维字符串数组

Question

This is my sample text file:

128_1   128_2   128_3   128_4   128_5   128_6   128_7   128_8
256_1   256_2   256_3   256_4   256_5   256_6   256_7   256_8
512_1   512_2   512_3   512_4   512_5   512_6   512_7   512_8

I am trying to convert this text file into 2d string array but cant get it right. I end up with Null values.

This is the output of my code when i run:

128_1 128_2 128_3 128_4 128_5 128_6 128_7 128_8
256_1 256_2 256_3 256_4 256_5 256_6 256_7 256_8
512_1 512_2 512_3 512_4 512_5 512_6 512_7 512_8
null null null null null null null null
null null null null null null null null
null null null null null null null null
null null null null null null null null
null null null null null null null null

This is what i have so far:

String[][] multi() {

  String[][] tobeReturned = null;
  BufferedReader reader = createReader("/numbers/_output.txt");

  String line;
  int row = 0;
  int size = 0;

  try {
    while ((line = reader.readLine()) != null) {
      String[] vals = line.trim().split("\t");

      if (tobeReturned == null) {
        size = vals.length;
        tobeReturned = new String[size][size];
        //println(size);
      }

      for (int col = 0; col < size; col++) {
        tobeReturned[row][col] = vals[col];
      }

      row++;     

      //println(row);
    }
  }
  catch(IOException e) {
  }

  for (String[] arr : tobeReturned) {
    println(arr);
  }

  return tobeReturned;
}

Answer 1

As said by previous your sizing is wrong. You know the size of the file so try this:

 row=0;
 tobeReturned = new String[3][8];
 while ((line = reader.readLine()) != null) {
  String[] vals = line.trim().split("\t");
  for (int col = 0; col < 8; col++) {
   tobeReturned[row][col] = vals[col];
 }
 row++;  
 }
 for(i=0; i<3; i++){
  for(j=0;j<8; j++){
   printlin(tobeReturned[i][j];
  }
 }   

Answer 2

String array creation is in error.

tobeReturned = new String[size][size];

This should be like

tobeReturned = new String[row][col];

Since, at first, you didn't count how many rows there are, you create a square matrix of column length.

If you really need to use String[][] you should also count the lines.

If you are using Java 8, I suggest you the following implementation:

public static String[][] strMatrix(String filePath) throws IOException {
        Stream<String> lines = Files.lines(Paths.get(filePath));
        String[][] strMat = lines.map(line -> line.split("\\s+")).toArray(String[][]::new);
        return strMat;
    }