Copy coordinates of one 2D array to another array

Question

I have a 2D array freeSpace[][] that represents x, y coordinates. If the space is "not free" then I have it marked as 77, other 1.

I want to put all the elements marked as 77 into it's own array, with those particular array coordinates. I think it should be simple, but I just can't get the syntax correct.

Here is my code:

for (int v = 0; v < info.getScene().getHeight(); v++) {
    for (int h = 0; h < info.getScene().getWidth(); h++) {
        //System.out.print(freeSpace[h][v] != 77 ? "." : "#");
        if (freeSpace[h][v] == 77) {
            blockedCoordinates = new int[][]{{h, v}};
        }
    }
    System.out.println();
}

I have already declared the blockedCoordinates[][] array.

Most of my attempts have lead to an empty array.

For each not free space you’re completely declaring a new blockedCoordinates array, overwriting anything previously there Can you give a small example of a grid (say, 3x3) and what you expect the blockedCoordinates array to look like afterwards?Additionally, for only two states, a boolean would suffice, or better yet, an enum So more can be added easily later. — BeUndead
– BeUndead, Commented Jun 9, 2021 at 1:13

Manifest Man · Accepted Answer · 2021-10-29 11:18:47Z

1

You are doing some error while copying your data, here is why:

// assuming following definition
int[][] blockedCoordinate = new int[][]{};

for (int v = 0; v < info.getScene().getHeight(); v++) {
    for (int h = 0; h < info.getScene().getWidth(); h++) {
        //System.out.print(freeSpace[h][v] != 77 ? "." : "#");
        if (freeSpace[h][v] == 77) {
            // Make a copy
            int[][] copyBlockedCoordinate = blockedCoordinates;
            // extend the array length by 1
            blockedCoordinates = new int[copyBlockedCoordinate.length + 1][2];
            for (int i = 0; i < copyBlockedCoordinate.length; i++) {
                for (int j = 0; j < copyBlockedCoordinate[i].length; j++) {
                    blockedCoordiante[i][j] = copyBlockedCoordinate[i][j];
                }
            }
            // add new array at new or last index position in blockedCoordinate array
            blockedCoordinate[copyBlockedCoordinate.length] = {h, v};
        }
    }
    // Make sure you write what you want to the console here to debug :)
    System.out.println();
}

edited Oct 29, 2021 at 11:18

answered Jun 9, 2021 at 1:52

Manifest Man

91511 silver badges16 bronze badges

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

7 Comments

drexl spivey Over a year ago

I get a new array which I have tested with blockedCoordinates.length, that seems to work (not sure if it copies the coordinates? Trying to figure out how to test that). I think it works tho. I had to comment the line blockedCoordinate[copyBlockedCoordinate] = {h, v}; because it was giving me a type error. Not sure what this does? Does it copy the coordinate location, to the next matrix -- in which case, it would not work, gonna see if I can figure out a more proper syntax for that line.

Manifest Man Over a year ago

You´re right, my bad, at that place i forgot. to add attribute .length at that line :)

Manifest Man Over a year ago

I also fixed it now, make sure to check it and mark it as answer.

drexl spivey Over a year ago

I was getting an error with the second part, "Arrays constants can only be used in initializers error" I fixed by editing the line: blocksArray[copyBlockedCoordinate.length] = new int[]{h, v}; It all seems to work, at least better than before, gotta keep working it. but I will mark it as answered for now =)

drexl spivey Over a year ago

After a couple days off this topic, I have returned to it. I am still getting an error, particularly on this line. Could someone explain to me what is happening, beyond the comment? =) // add new array at new index position blocksArray[blocksArray.length] = new int[]{xPixels, yPixels}; I am getting an error: java.lang.ArrayIndexOutOfBoundsException: Index 1 out of bounds for length 1. I am researching that now.

|

Collectives™ on Stack Overflow

Copy coordinates of one 2D array to another array

1 Answer 1

7 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

7 Comments

Your Answer

Sign up or log in

Post as a guest

Related