js double array code example

Example 1: js array two dimensional

// declaration of a two-dimensional array
// 5 is the number of rows and 4 is the number of columns.
const matrix = new Array(5).fill(0).map(() => new Array(4).fill(0));

console.log(matrix[0][0]); // 0

Example 2: javascript create 2d array

function create2DArray(rows, columns, value = (x, y) => 0) {
  var array = new Array(rows);
  for (var i = 0; i < rows; i++) {
    array[i] = new Array(columns);
    for (var j = 0; j < columns; j++) {
      array[i][j] = value(i, j);
    }
  }

  return array;
}

var array = create2DArray(2, 3, (row, column) => row + column);
console.log(array);
//output: [[0, 1, 2],
//         [1, 2, 3]]

Example 3: how to double array data in js

function double (arr){
    let newArr = [];
    for(let i = 0; i < arr.length; i++){
        newArr.push(arr[i] * 2);
    }
    console.log(newArr) ;
}
console.log(double([3,4,5]));