Getting the value of particular element in a 2 - D Array in Javascript

Question

I wanted to know how to find a particular element say element at this array[2][3] position. I tried displaying all the elements but dint know how to print a particular value. i tried displaying the value but it displays undefined. Can you please help me in displaying particular value.

var array1 = new Array(3);

//2D array creation
for (var i = 0; i < 3; i++) {
  array1[i] = new Array(3);
}

var abc = 1;
for (var i = 0; i < 3; i++) {
  for (var j = 0; j < 3; j++) {
    array1[i][j] = abc;
    abc = abc + 1;
  }
}

for (var i = 0; i < 3; i++) {
  for (var j = 0; j < 3; j++) {
    document.write(array1[i][j] + " ");    
  }

  //alert(array1[2][3]);
  document.write("<br/>");
}

<!DOCTYPE HTML>
  <html>
	<head>
	  <title>Array Comparison</title>
    </head>
    <body>
    </body>
  </html>

avoid creating arrays with Array constructor, as you are using loops you can use push() method to add an item — Pranay Kumar
– Pranay Kumar, Commented Sep 4, 2017 at 16:51
As I see you don't have the 3 index in your array: array[2][3]. Your array is a 3x3, so if you try to access your [3] index, it will try to access your fourth element, and thats result in undefined. The lastest element is array[2][2]. — L. Figueredo
– L. Figueredo, Commented Sep 4, 2017 at 16:52

Andy · Accepted Answer · 2017-09-04 17:01:35Z

1

If your array is like this:

[
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
]

The [2][3] position doesn't exist. Your array is a 3x3, so if you try to access your [3] index, it will try to access your fourth element, and that results in undefined. The lastest element is array[2][2].

In Javascript your arrays are always zero based index. So your first element is on [0] position.

edited Sep 4, 2017 at 17:01

Andy

63.6k13 gold badges72 silver badges99 bronze badges

answered Sep 4, 2017 at 16:55

L. Figueredo

2782 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

brk · Accepted Answer · 2017-09-04 16:56:33Z

0

array1 is [[1,2,3],[4,5,6],[7,8,9]][[1,2,3],[4,5,6],[7,8,9]][[1,2,3],[4,5,6],[7,8,9]]

So array array1[2] will try to retrieve the element from index 2 which is

[7,8,9][7,8,9][7,8,9]

array1[2][3] will try to retrieve element from 3 index that is 4th position ,from result of array1[2] there is no element in third index, so there is undefined

answered Sep 4, 2017 at 16:56

brk

50.3k10 gold badges59 silver badges85 bronze badges

Collectives™ on Stack Overflow

Getting the value of particular element in a 2 - D Array in Javascript

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related