Java: Converting ints to Strings in 2d array

Question

I have sa 2-dimensional array with lots of rows and columns, with random numbers between 0 and 255. I'm trying to look for instances of particular integers within my array, ie those between 231 and 255, and simply print out a String, ie "/", "." or a space, each time it comes across such integers. I suppose the following code only works for columns. How might I extend this into rows?

int[][] result = function(parameter);

System.out.println(Arrays.deepToString(result));
for (int i = 1; i <= result.length-1; i++) {
    if (result[i][i] >= 179 && result[i][i] <= 204) {
        System.out.print("\\");
    }   
    if (result[i][i] >= 205 && result[i][i] <= 230) {
        System.out.print(".");
    }   
    if (result[i][i] >= 231 && result[i][i] <= 255) {
        System.out.print(" ");
    }
}

Answer 1

You code is only testing elements on the diagonal of the 2d array. You should have a nested loop in order to loop over the entire array :

for (int i = 0; i <= result.length-1; i++) {
  for (int j = 0; j <= result[i].length-1; j++) {
    if (result[i][j] >= 179 && result[i][j] <= 204) {
        System.out.print("\\");
    }   
    if (result[i][j] >= 205 && result[i][j] <= 230) {
        System.out.print(".");
    }   
    if (result[i][j] >= 231 && result[i][j] <= 255) {
        System.out.print(" ");
    }
  }
  System.out.println("");
}

Answer 2

You can simply traverse the rows as well, If I understood what you want correctly

int[][] result = function(parameter);

System.out.println(Arrays.deepToString(result));
for (int row = 0; row < result.length; row++) {     
    for (int col= 0; col< result[0].length; col++) {
        if (result[row][col] >= 179 && result[row][col] <= 204) {
            System.out.print("\\");
        }   
        if (result[row][col] >= 205 && result[row][col] <= 230) {
            System.out.print(".");
        }   
        if (result[row][col] >= 231 && result[row][col] <= 255) {
            System.out.print(" ");
        }
    }
}

Answer 3

you can use the following ways to convert an integer into string

Integer.toString(i) or String.valueOf(i)

Example:

Integer.toString(result[i][j])

String.valueOf(result[i][j])

anyway your problem is that you need two loops one for rows and 2nd for columns, that is why you are getting only the values of columns :)

int[][] result = function(parameter);

System.out.println(Arrays.deepToString(result));
for (int row = 0; row < result.length; row++) {     
    for (int col= 0; col< result[0].length; col++) {
        if (result[row][col] >= 179 && result[row][col] <= 204) {
            System.out.print("\\");
        }   
        if (result[row][col] >= 205 && result[row][col] <= 230) {
            System.out.print(".");
        }   
        if (result[row][col] >= 231 && result[row][col] <= 255) {
            System.out.print(" ");
        }
    }
}

Answer 4

If I understand your question, then I believe the easiest approach is to use a StringBuilder and dynamically build your output String . Iterate each array in your multidimensional array, and test each value (using else so that each test doesn't logically exclude the previous tests) like

int[][] result = { { 1, 179 }, { 205, 231 }, { 256 } };
StringBuilder sb = new StringBuilder("[");
for (int i = 0; i < result.length; i++) {
    int[] arr = result[i];
    if (i != 0) {
        sb.append(", ");
    }
    sb.append("[");
    for (int j = 0; j < arr.length; j++) {
        if (j != 0) {
            sb.append(", ");
        }
        if (arr[j] >= 179 && arr[j] <= 204) {
            sb.append("\\");
        } else if (arr[j] >= 205 && arr[j] <= 230) {
            sb.append(".");
        } else if (arr[j] >= 231 && arr[j] <= 255) {
            sb.append(" ");
        } else {
            sb.append(arr[j]);
        }
    }
    sb.append("]");
}
sb.append("]");
System.out.println(sb.toString());

Output is

[[1, \], [.,  ], [256]]