JavaScript Multidimensional array
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Multidimensional arrays
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.
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];
var salary = [arr1, arr2, arr3, arr4, arr5];
Accessing the element of salary array:
salary[0][2];
salary[3][2]; // Selects 28000
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