2D Array with a custom rows and columns

Question

I need to create 2d array with 5 rows and 6 columns in the first row and then the rest is 5 columns

so that would look like this

{ 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   }

is there any way to do so?

as of now i have only this, it creates 6 rows and 5 columns:

private static JButton[][] b = new JButton[6][5];

updtae: I am using Java for this.

You might want to tag this question for the language you're using — lurker
– lurker, Commented Apr 16, 2014 at 0:09
What's the "use case" for this? It might logically lend itself to two arrays: one that is 1x6, and another that's 5x5. Managing it may be simpler as well. — lurker
– lurker, Commented Apr 16, 2014 at 0:11
@lurker Actually the other would be 4x5, not 5x5. But I agree with the idea of separation. — Joffrey
– Joffrey, Commented Apr 16, 2014 at 0:30

Joffrey · Accepted Answer · 2014-04-16 01:04:30Z

2

You can initialize your array in 2 steps:

// initialize the first dimension
private static JButton[][] b = new JButton[5][];

// initialize the second dimension
static {
    b[0] = new JButton[6];
    for (int i = 1; i < b.length; i++) {
        b[i] = new JButton[5];
    }
}

When you initialize only the first dimension, it creates an array of rows, in which each row is null.

During the second step, you create each row of the desired length.

edited Apr 16, 2014 at 1:04

answered Apr 16, 2014 at 0:17

Joffrey

38.3k8 gold badges90 silver badges118 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Eddie Curtis · Accepted Answer · 2014-04-16 00:16:29Z

0

This isn't possible.

You can however, create a 6x6 array and not use the 6th column in every row you don't want to.

{ 0 0 0 0 0 0
  0 0 0 0 0 null
  0 0 0 0 0 null
  0 0 0 0 0 null
  0 0 0 0 0 null  }

answered Apr 16, 2014 at 0:16

Eddie Curtis

1,2378 silver badges21 bronze badges

1 Comment

Joffrey Over a year ago

Yes it is possible. Look at my answer.

teagles · Accepted Answer · 2014-04-16 00:42:02Z

0

Would something like this suit?

JButton[][] s = new JButton[5][];
for (int i = 0; i< 5; i++){
    if (i == 0) {
        s[i] = new JButton[6];
    } else {
        s[i] = new JButton[5];
    }
}

edited Apr 16, 2014 at 0:42

answered Apr 16, 2014 at 0:19

teagles

1311 gold badge1 silver badge6 bronze badges

3 Comments

Eddie Curtis Over a year ago

Both branches of that if are doing the same thing.

Joffrey Over a year ago

You did not consider the static context of the variable. Moreover, there is a typo where you probably meant 5 instead of 6.

teagles Over a year ago

Fixed for typo but the other answer deals with the static context.

b8ckwith · Accepted Answer · 2014-04-16 01:21:36Z

0

I actually figured it out. Here is my way of doing it:

private static JButton[][] b = {{new JButton(), new JButton() , new JButton() , new JButton() , new JButton() , new JButton() },
        {new JButton(), new JButton() , new JButton() , new JButton() , new JButton()}, 
        {new JButton(), new JButton() , new JButton() , new JButton() , new JButton()},
        {new JButton(), new JButton() , new JButton() , new JButton() , new JButton()},
        {new JButton(), new JButton() , new JButton() , new JButton() , new JButton()}};

and then I just add them to a panel

for (int i = 0; i < b.length; i++) {
            for (int j = 0; j <b[i].length; j++) {

                panel.add(b[i][j]);

           }

        }

answered Apr 16, 2014 at 1:21

b8ckwith

959 bronze badges

1 Comment

Joffrey Over a year ago

"your way" is really painful to use, what if you had a 256*256 array? Copy paste?

Collectives™ on Stack Overflow

2D Array with a custom rows and columns

4 Answers 4

Comments

1 Comment

3 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

1 Comment

3 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related