I have an array of 800 objects.
cells = [
{ x_position: 0, y_position: 0, terrain: 'water' },
{ x_position: 0, y_position: 1, terrain: 'water' },
{ x_position: 0, y_position: 2, terrain: 'water' },
{ x_position: 0, y_position: 3, terrain: 'water' },
{ x_position: 0, y_position: 4, terrain: 'water' },
...
]
Let's say for some x_position and y_position I want to change the terrain to 'land'.
How can I iterate through the array changing the terrain?
You can use forEach():
let cells = [
{ x_position: 0, y_position: 0, terrain: 'water' },
{ x_position: 0, y_position: 1, terrain: 'water' },
{ x_position: 0, y_position: 2, terrain: 'water' },
{ x_position: 0, y_position: 3, terrain: 'water' },
{ x_position: 0, y_position: 4, terrain: 'water' }
];
let match = {
x_position: 0,
y_position: 2
}
cells.forEach(o => {
if(o.x_position == match.x_position && o.y_position == match.y_position)
o.terrain = 'land';
});
console.log(cells);You can use Array.prototype.map to iterate over the array and change the object's terrain value;
Pay attention that my solution is immutable, meaning, it not changes the original array nor the objects.
const cells = [{
x_position: 0,
y_position: 0,
terrain: 'water'
},
{
x_position: 1,
y_position: 1,
terrain: 'water'
},
{
x_position: 0,
y_position: 2,
terrain: 'water'
},
{
x_position: 0,
y_position: 3,
terrain: 'water'
},
{
x_position: 0,
y_position: 4,
terrain: 'water'
}
];
const result = cells.map((item) => {
if (item.x_position === 1) {
return { ...item,
terrain: 'land'
}
} else {
return item;
}
});
console.log(result)Simply Use this Code.
var cells = [
{ x_position: 0, y_position: 0, terrain: 'water' },
{ x_position: 0, y_position: 1, terrain: 'water' },
{ x_position: 0, y_position: 2, terrain: 'water' },
{ x_position: 0, y_position: 3, terrain: 'water' },
{ x_position: 0, y_position: 4, terrain: 'water' },
];
var i;
for (i = 0; i < cells.length; i++) {
cells[i].land = cells[i]['terrain'];
delete cells[i].terrain;
} console.log(cells);
In the long term it might be good to build up a position hashmap:
const byPosition = {};
for(const cell of cells)
byPosition[cell.position_x + "|" + cell.position_y] = cell;
So you can simply do:
byPosition["1|2"].terrain = "landscape";
If your cells are somehow forming a square you should definetly use a 2d array to store them.
You can find the element with array.prototype.find then change value of terain property to Land:
var cells = [
{ x_position: 0, y_position: 0, terrain: 'water' },
{ x_position: 0, y_position: 1, terrain: 'water' },
{ x_position: 0, y_position: 2, terrain: 'water' },
{ x_position: 0, y_position: 3, terrain: 'water' },
{ x_position: 0, y_position: 4, terrain: 'water' }
];
var x = 0, y = 2;
var item = cells.find(c => c.x_position === x && c.y_position === y);
item && item.terrain = 'land';
