How to move an element in 2D array between other arrays ? Javascript-CodePudding

Example of the array:

let arr = [
  [1, 1, 1, 1],
  [2, 2, 2, 2],
  [3, 3, 3, 0],
];

I want to be able to move the '0' left, right, up and down.

for example moving the '0' element up:

[
  [1, 1, 1, 1],
  [2, 2, 2, 0], //<---
  [3, 3, 3, 2],
];

I have been able to move the element LEFT and RIGHT with a function as shown below:

function changePosition(arr, from, to) {
  arr.splice(to, 0, arr.splice(from, 1)[0]);
  return arr;
}

I'd like to some how move the element UP and DOWN. I would appreciate a hand on this code since I haven't found much on the internet.

CodePudding user response：

you can do something like this

let arr = [
  [1, 1, 1, 1],
  [2, 2, 2, 2],
  [3, 3, 3, 0],
];

const findPos = () => {
  const y = arr.findIndex(a => a.includes(0))
  return [arr[y].indexOf(0), y]
}

const up = () => {
  const [x, y] = findPos()
  if (y <= 0) {
    return;
  }
  let temp = arr[y - 1][x]
  arr[y - 1][x] = 0
  arr[y][x] = temp

}

const down = () => {
  const [x, y] = findPos()
  if (y >= arr.length - 1) {
    return;
  }
  let temp = arr[y   1][x]
  arr[y   1][x] = 0
  arr[y][x] = temp
}

const left = () => {
  const [x, y] = findPos()
  if (x <= 0) {
    return;
  }
  let temp = arr[y][x -1]
  arr[y][x - 1] = 0
  arr[y][x] = temp
}

const right = () => {
  const [x, y] = findPos()
  if (x >= arr[y].length - 1) {
    return;
  }
  let temp = arr[y][x   1]
  arr[y][x   1] = 0
  arr[y][x] = temp
}

console.log(arr, findPos())
up()
console.log(arr, findPos())
left()
console.log(arr, findPos())
down()
console.log(arr, findPos())

CodePudding user response：

You can try to swap the values to whatever index you like.

     function swap(yourArray,topOrBottomArray,positionOfYourNum){   
     //positionOfYourNum is 3 in your case
     let temp = yourArray[positionOfYourNum];
     yourArray[positionOfYourNum] = topOrBottomArray[positionOfYourNum];
     topOrBottomArray[positionOfYourNum] = temp;
     }

Then just call

     swap(arr[2],arr[1],3);  //3 is the index of 0
     console.log(arr);

Result = [
  [1, 1, 1, 1],
  [2, 2, 2, 0], 
  [3, 3, 3, 2],
];