storing coordinates in array in javascript

Question

I want to store coordinates into an array in javascript, I am new to javascript and do not have an idea how to do it.

Any help would be appreciated.

Solution 1

There are a number of ways to store x,y coordinates:

Option 1 (every other index in an array):

function storeCoordinate(x, y, array) {
    array.push(x);
    array.push(y);
}

var coords = [];
storeCoordinate(3, 5, coords);
storeCoordinate(19, 1000, coords);
storeCoordinate(-300, 4578, coords);

coords[0] == 3   // x value (even indexes)
coords[1] == 5   // y value (odd indexes)

// to loop through coordinate values
for (var i = 0; i < coords.length; i+=2) {
    var x = coords[i];
    var y = coords[i+1];
} 

Option 2 (simple object in an array):

function storeCoordinate(xVal, yVal, array) {
    array.push({x: xVal, y: yVal});
}

var coords = [];
storeCoordinate(3, 5, coords);
storeCoordinate(19, 1000, coords);
storeCoordinate(-300, 4578, coords);

coords[0].x == 3   // x value
coords[0].y == 5   // y value

// to loop through coordinate values
for (var i = 0; i < coords.length; i++) {
    var x = coords[i].x;
    var y = coords[i].y;
} 

Solution 2

Well, let's say we make it simple, you want to store coördinates, so we have x and y:

function coordinate(x, y) {
    this.x = x;
    this.y = y;
}

This is how you create Objects in javascript, they act like functions. With this function you can create your coordinates. Then all you need to do is create an array:

var arr = new Array();
arr.push(new coordinate(10, 0));
arr.push(new coordinate(0, 11));

That's it basically

Solution 3

The push method would do the job:

var arr = new Array();

arr.push({ x : x_coordinate, y : y_coordinate });

You can then access them by using

arr[0].x (gives the x coordinate)

and

arr[0].y (gives the y coordinate).

Hope it helps.

Solution 4

These answers are not usable if you're trying to store a grid/matrix that you wanted to access data point by x,y values later.

var coords = [];

for(y=0; y < rows; y++){
   for(x=0;x<cols; x++){
      if(typeof coords[x] == 'undefined']){
         coords[x] = [];
      }

      coords[x][y] = someValue;
   }
}

//accessible via coords[x][y] later

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