Initialize a two-dimensional array in JavaScript

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I would like to create a two-dimensional array that gets initialized with booleans which are set to false. Currently I'm using this method of array creation:

const rows = 3
const cols = 5

const nestedArray = new Array(rows).fill(
    new Array(cols).fill(false)
)

The nestedArray looks fine, but as soon as I change the value of nestedArray[0][2], the values of nestedArray[1][2] and nestedArray[2][2] also get changed.

I guess this is because the sub-arrays are identical, probably because they get filled into the parent array by reference and not by value.

What would be an elegant and efficient way of creating an array of non-identical sub-arrays instead?

You can use nested Array.from() calls:

const rows = 3
const cols = 5

const nestedArray = Array.from({ length: rows }, () => 
  Array.from({ length: cols }, () => false)
);
  
nestedArray[0][1] = 'value'; // example of changing a single cell
  
console.log(nestedArray);

How to create two dimensional array in JavaScript?, The two-dimensional array is an array of arrays, so we create an array of one-​dimensional array objects. The following program shows how to create an 2D array  "Javascript does not support multi-dimensional arrays" - But array of arrays provide the equivalent of multi-dimensional arrays, so you can say JavaScript DOES support multi-dimensional arrays (even if they are not truly multi-dimensional, I think your first sentence is not truly correct in this form :) ).

You could use Array.from method to create rows where second parameter is map method, and Array.fill for columns.

const rows = 3
const cols = 5

const nestedArray = Array.from(Array(rows), _ => Array(cols).fill(false));
nestedArray[0][1] = true;
console.log(nestedArray)

Learn JavaScript Multidimensional Array By Examples, JavaScript doesn't provide the multidimensional array.This tutorial shows you how to create a JavaScript multidimensional array by using an array of arrays. How to declare , initialize and use 2 dimensional arrays in javascript, If I write var arr=new array(2,2) is it correct to declare a array with 2 rows and two columns and is it fine if i decl

const nestedArray = Array(rows).fill(false).map(x => Array(cols).fill(false))

try this one

How to declare and initialize multidimensional arrays JS?, I'm trying to use a multidimensional array for this but I have problems initializing the array with set values. public var multiDimensionalArray: int[,]  The most common way to declare and initialize two dimensional arrays in Java is using shortcut syntax with array initializer: int[][] arr = { {1, 2, 3}, {4, 3, 6}, {7, 8, 9} }; 1

Maybe something like:

const rows = 3
const cols = 5

const nestedArray = new Array(rows).fill(0);

nestedArray.forEach((e, i, a) => a[i] = new Array(cols).fill(false));

console.log(nestedArray);

Creating a custom two-dimensional Array, Click here to learn how to create two dimensional arrays in JavaScript. we incremented through the entire original array, declaring a new array at each "stop​". Initialize new arrays as you declare them If you call the constructor with two or more arguments, the arguments initialize the array elements. If you only supply one argument to the Array constructor, the argument initializes the length of the new array; the new array’s elements are not initialized.

In JavaScript, how do you create an empty 2D array?, How to create an empty 2D array: [code]var twoD = [[], []]; [/code]How to create a Peter Carroll, Full stack developer, mainly JavaScript tech. What will happen if you put too few elements in an array when you initialized it? JavaScript does not provide the multidimensional array natively. However, you can create a multidimensional array by defining an array of elements, where each element is also another array. For this reason, we can say that a JavaScript multidimensional array is an array of arrays.

Creating two dimensional array in javascript, Multidimensional Arrays JavaScript does not support true multidimensional new Array ( 10 ); // Each row has 10 columns // Initialize the array for ( var row = 0​  Arrays are a special type of objects. The typeof operator in JavaScript returns "object" for arrays. But, JavaScript arrays are best described as arrays. Arrays use numbers to access its "elements". In this example, person[0] returns John:

Multidimensional Arrays, Question: How do I create a two-dimensional array in JavaScript? Then, in the outer for loop, each element of f is itself initialized as new Array() ; thus f  The two-dimensional array is an array of arrays, that is to say, to create an array of one-dimensional array objects. They are arranged as a matrix in the form of rows and columns. JavaScript suggests some methods of creating two-dimensional arrays.

Comments
  • Possible Duplicate stackoverflow.com/questions/18163234/…
  • Why dont you try using json?
  • While this answer is probably correct and useful, it is preferred if you include some explanation along with it to explain how it helps to solve the problem. This becomes especially useful in the future, if there is a change (possibly unrelated) that causes it to stop working and users need to understand how it once worked.