Multidimensional array in JavaScript

Last Updated : 27 Jul, 2021

Multidimensional arrays are not directly provided in JavaScript. If we want to use anything which acts as a multidimensional array then we need to create a multidimensional array by using another one-dimensional array. So multidimensional arrays in JavaScript is known as arrays inside another array. We need to put some arrays inside an array, then the total thing is working like a multidimensional array. The array, in which the other arrays are going to insert, that array is use as the multidimensional array in our code. To define a multidimensional array its exactly the same as defining a normal one-dimensional array.

One-Dimensional array:

Hey geek! The constant emerging technologies in the world of web development always keeps the excitement for this subject through the roof. But before you tackle the big projects, we suggest you start by learning the basics. Kickstart your web development journey by learning JS concepts with our JavaScript Course. Now at it's lowest price ever!

var arr = []; // Empty 1D array
var arr1 = ["A", "B", "C", "D"] // 1D array contains some alphabets
var arr1 = [1, 2, 3, 4, 5] // 1D array contains some digits

Multidimensional-Dimensional array:

Method 1:

1st, need to define some 1D array
var arr1 = ["ABC", 24, 18000];
var arr2 = ["EFG", 30, 30000];
var arr3 = ["IJK", 28, 41000];
var arr4 = ["EFG", 31, 28000];
var arr5 = ["EFG", 29, 35000];
// "salary" defines like a 1D array but it already contains some 1D array
var salary = [arr1, arr2, arr3, arr4, arr5];

Here arr1, arr2, …arr5 are some 1D arrays which are inside salary array.

Method 2:

var salary = [
   ["ABC", 24, 18000],
   ["EFG", 30, 30000],
   ["IJK", 28, 41000],
   ["EFG", 31, 28000],
];

Here, salary array works like a multidimensional array. This notations are known as array literals.

Accessing the element of salary array:

To access the array element we need a simple index based notation

// This notation access the salary of "ABC" person which is 18000, 
// [0] selects 1st row, and [2] selects the 3rd element
// of that 1st row which is 18000
salary[0][2];

// Similarly, 
salary[3][2]; // Selects 28000

**This notation is used for both Method 1 and Method 2.

For many iteration, we need to use loop to access the elements,

// This loop is for outer array
for (var i = 0, l1 = salary.length; i < l1; i++) {

    // This loop is for inner-arrays
    for (var j = 0, l2 = salary[i].length; j < l2; j++) {

        // Accessing each elements of inner-array
        documents.write( salary[i][j] ); 
    }
}

Adding elements in Multidimensional Array: Adding elements in multi-dimensional arrays can be achieved in two ways in inner array or outer array. The inner array can be done in two different ways.

Adding elements to inner array:

We can use simple square bracket notation to add elements in multidimensional array.

salary[3][3] = "India";

// It adds "India" at the 4th index of 4th sub-array,
// If we print the entire 4th sub-array, document.write(salary[3]);
// the output will be :  ["EFG", 31, 28000, "India"]
// indexing starts from 0

We can use push() method to add elements in the array.

salary[3].push("India", "Mumbai");

// It add "India" at the 4th index and "Mumbai" at
// 5th index of 4th sub-array
// If we print the entire 4th sub-array,
// document.write(salary[3]);
// The output will be :  ["EFG", 31, 28000, "India", "Mumbai"]
// Indexing starts from 0

Adding elements to outer array: It is much similar to previous methods.

salary.push(["MNO", 29, 33300]);
// This row added after the last row in the "salary" array

Removing elements in Multidimensional Array: We can use pop() methods to remove elements from inner-arrays, and also use pop() method for removing a entire inner array.

// Remove last element from 4th sub-array
// That is 28000 indexing starts from 0
salary[3].pop(); 

// Removes last sub-array
// That is "["EFG", 31, 28000]"
salary.pop();

Example 1:

// Prints a simple multidimensional array in JavaScript
<script>
var arr1 = ["ABC", 24, 18000];
var arr2 = ["EFG", 30, 30000];
var arr3 = ["IJK", 28, 41000];
var arr4 = ["EFG", 31, 28000];
var arr5 = ["EFG", 29, 35000];
var salary = [arr1, arr2, arr3, arr4, arr5]; 
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
</script>

Output:

ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000
EFG, 31, 28000
EFG, 29, 35000

Example 2:

// Prints a simple multidimensional array in
// JavaScript with different declaration
<script>
var salary = [
   ["ABC", 24, 18000],
   ["EFG", 30, 30000],
   ["IJK", 28, 41000],
   ["EFG", 31, 28000],
]; 
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
</script>                    

Output:

ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000
EFG, 31, 28000
EFG, 29, 35000

Example 3:

// Prints a simple multidimensional array in JavaScript
// where we just print the salary of a specific person
<script>
var salary = [
   ["ABC", 24, 18000],
   ["EFG", 30, 30000],
   ["IJK", 28, 41000],
   ["EFG", 31, 28000],
]; 
document.write("salary of 2nd person : " + salary[1][2] + "<br>");
document.write("salary of 4th person : " + salary[3][2] + "<br>");
</script>                    

Output:

salary of 2nd person : 30000
salary of 4th person : 28000

Example 4:

// Prints a simple multidimensional array in
// JavaScript where we add elements in the array 
// using simple square bracket and push() method
<script>
var salary = [
   ["ABC", 24, 18000],
   ["EFG", 30, 30000],
   ["IJK", 28, 41000],
   ["EFG", 31, 28000],
]; 
  
// Prints first array
document.write("Original array :<br>");
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
  
// Adding "India" at the 4th index of 4th sub array
salary[3][3] = "India";
  
document.write("<br>after adding \"India\" at the 4th array :<br>");
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
  
document.write("<br>after adding \"USA\" and \"Canada\" "
     + "at the 3rd array using \"push()\" method :<br>");
salary[2].push("USA", "Canada");
  
// Adding "USA" and "Canada" in the 2nd sub-array
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
</script> 

Output:

Original array :
ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000
EFG, 31, 28000

after adding "India" at the 4th array :
ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000
EFG, 31, 28000, India

after adding "USA" and "Canada" at the 3rd array using "push()" method :
ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000, USA, Canada
EFG, 31, 28000, India

Example 5:

// Prints a simple multidimensional array in
// JavaScript where we add a new inner array 
<script>
var salary = [
   ["ABC", 24, 18000],
   ["EFG", 30, 30000],
   ["IJK", 28, 41000],
   ["EFG", 31, 28000],
]; 
  
// Prints first array
document.write("Original array :<br>");
  
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
  
document.write("<br>After adding a new inner array :<br>");
  
// Pushing a new sub-array
salary.push(["MNO", 29, 33300]);
  
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
</script> 

Output:

Original array :
ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000
EFG, 31, 28000

After adding a new inner array :
ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000
EFG, 31, 28000
MNO, 29, 33300

Example 6:

// Prints a simple multidimensional array in
// JavaScript where we remove a single element
//and a entire sub-array
<script>
var salary = [
   ["ABC", 24, 18000],
   ["EFG", 30, 30000],
   ["IJK", 28, 41000],
   ["EFG", 31, 28000],
]; 
  
// Prints first array
document.write("Original array :<br>");
  
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
  
document.write("<br>After removing last element " 
            + "of last inner array :<br>");
  
// Removes the last element of 3rd sub-array
salary[3].pop();
  
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
  
document.write("<br>After removing last inner array :<br>");
  
// Removes last sub-array
salary.pop();
  
for(var i = 0; i < salary.length; i++) {
    document.write(salary[i] + "<br>");
}
</script> 

Output:

Original array :
ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000
EFG, 31, 28000

After removing last element of last inner array :
ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000
EFG, 31

After removing last inner array :
ABC, 24, 18000
EFG, 30, 30000
IJK, 28, 41000

JavaScript is best known for web page development but it is also used in a variety of non-browser environments. You can learn JavaScript from the ground up by following this JavaScript Tutorial and JavaScript Examples.

My Personal Notes

Related Articles

Table of Contents

Multidimensional array in JavaScript

Start Your Coding Journey Now!