How to format an array of integers in java

Question

Currently I have the following method:

public static void printDoubleIntArray(int[][] doubleIntArray) {
for (int x = 0; x < doubleIntArray.length; x++) {
    System.out.println();
    for (int y = 0; y < doubleIntArray[x].length; y++) {
    System.out.print(doubleIntArray[x][y]);
    }
}
}

It works perfectly when the parameter "doubleIntArray" is only numbers from 0 - 9 like in the following print out:

However, if the integers in each element of the array become larger than 9 then I get something like the following:

0000000
000121797
001717171716
0101617171617
001616161617
081617161717
001417171716

What I would like to know is how do I make the above example print out like so:

0   0   0   0   0   0   0
0   0   0  12  17   9   7
0   0  17  17  17  17  16
0  10  16  17  17  16  17
0   0  16  16  16  16  17
0   8  16  17  16  17  17
0   0  14  17  17  17  16

Try this. docs.oracle.com/javase/tutorial/java/data/numberformat.html — Tony Ennis
– Tony Ennis, Commented Jul 4, 2013 at 16:02
So do that? Use tab (\t) or compute the number of spaces required by checking the length of the double after converting to string. — Brian Roach
– Brian Roach, Commented Jul 4, 2013 at 16:03

Cristian Meneses · Accepted Answer · 2013-07-04 16:04:37Z

2

You could try using java.text.NumberFormat and a pattern that displays every number with a fixed width.. Then concatenate them all in a single line...

answered Jul 4, 2013 at 16:04

Cristian Meneses

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Comments

Philipp Sander · Accepted Answer · 2013-07-04 16:13:25Z

2

System.out.print(doubleIntArray[x][y] + "\t");

\t prints a tab

but in this case it will print something like this: (but i guess thats okay for you)

0   0   0   0   0   0   0
0   0   0   12  17  9   7
0   0   17  17  17  17  16
0   10  16  17  17  16  17
0   0   16  16  16  16  17
0   8   16  17  16  17  17
0   0   14  17  17  17  16

edited Jul 4, 2013 at 16:13

answered Jul 4, 2013 at 16:04

Philipp Sander

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1 Comment

Luiggi Mendoza Over a year ago

It will heavily depend how OP wants to format the numbers for their consumption. For instance, since it looks for basic display purposes, this is a possible solution. Note that if you want a decent presentation format, it would be better using String#format instead.

Luiggi Mendoza · Accepted Answer · 2013-07-04 16:35:06Z

2

Or use String.format("%4d", myinteger) to have each integer occupy 4 chars, and be properly right padded.

edited Jul 4, 2013 at 16:35

Luiggi Mendoza

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answered Jul 4, 2013 at 16:11

Ayman

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Alex Gittemeier · Accepted Answer · 2013-07-04 16:11:01Z

1

System.out.printf("%4d", doubleIntArray[x][y]);

4 represents the minimum space that the number will print.

The other options for this method are explained here

answered Jul 4, 2013 at 16:11

Alex Gittemeier

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Luiggi Mendoza · Accepted Answer · 2013-07-04 16:38:15Z

1

You have 2 options. Firstly, you can use \t in the second for loop. But I think you could add \t and whitespace character to avoid deterioration. Can provide this too, adding if-else structure in second for loop. I mean

if(doubleIntArray[y].length<10){
    System.out.print(doubleIntArray[x][y] + "\t  ");
    //Tab+two whitespace.
} else {
    if(doubleIntArray[y].length>10) {
        System.out.print(doubleIntArray[x][y] + "\t ");
        //Tab+one whitespace
    } else {
        System.out.print(doubleIntArray[x][y] + "\t");
        //Tab+NO whitespace
    }
}

Logic is that I think. Sorry for my answers design. I am on the bus now and I cannot write smoothly. If I had a mistake sorry about that again.

edited Jul 4, 2013 at 16:38

Luiggi Mendoza

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answered Jul 4, 2013 at 16:28

TeachMeJava

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Comments

Dejan Ciev · Accepted Answer · 2013-07-05 11:29:28Z

0

public static void printDoubleIntArray(int[][] doubleIntArray) {
for (int x = 0; x < doubleIntArray.length; x++) {
System.out.println();
 for (int y = 0; y < doubleIntArray[x].length; y++) {
System.out.print(doubleIntArray[x][y],"\t");
    }
 System.out.print("\n");
}
}

answered Jul 5, 2013 at 11:29

Dejan Ciev

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