CODEWITHSUNDEEP
javaformattingmultidimensional-array
Primigenia
Primigenia

Reputation: 125

Formatting doubles inside a 2D array

I have a 2D array of doubles that have been calculated from other doubles. I want the doubles that are stored in the 2D array to be formatted so that they are to 4 decimal places. for example I have an array of:

fragmentMases = [363.076328934]      [668.128613182]      [974.16124702]      [1303.232096646]
                [283.109998526]      [588.162282774]      [894.194916612]     [1223.265766238]
                [1398.2454009859998] [1053.1796367379998] [748.1273524899999] [442.0947186519999]
                [1285.22153196]      [940.1557677119999]  [635.103483464]     [329.070849626]

But I want it to be:

fragmentMases = [363.0763]  [668.1286]  [974.1612] [1303.2320]
                [283.1099]  [588.1622]  [894.1949] [1223.2657]
                [1398.2454] [1053.1796] [748.1273] [442.0947]
                [1285.2215] [940.1557]  [635.1034] [329.0708]

I have made a function that I thought would do it but it doesn't seem to save it inside the array:

public static void formatArray(double[][] array) {

    Formatter fmt = new Formatter();

    for(int i = 0; i < 4; i++){
        for(int y = 0; y < array.length; y++){
            String.valueOf(array).length();
                fmt.format("%.4f", array[i][y]);
        }
    }
}

EDIT

So I run the following:

formatArray(fragmentMasses);

After running this I print out the array and none of the doubles are formatted.

Could anyone help me get this to work and save the formatted 2D array?

Thanks

Upvotes: 1

Views: 1722

Answers (1)

alexblum
alexblum

Reputation: 2238

You can create new array and override yours with it:

public static double[][] formatArray(double[][] array) {

    double[][] newArray = new double[array.length][array[0].length];
    for(int i = 0; i < array.length; i++){
        for(int y = 0; y < array[0].length; y++){
            newArray[i][y] = (double)Math.round(array[i][y] * 10000) / 10000;
        }
    }
    return newArray;
}

or you can change your own array:

  public static void formatArray(double[][] array) {
        for(int i = 0; i < array.length; i++){
            for(int y = 0; y < array[0].length; y++){
                array[i][y] = (double)Math.round(array[i][y] * 10000) / 10000;
            }
        }

    }

Upvotes: 2

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