In this article, we will learn how to create an array containing non-repeating elements in JavaScript.
The following are the two approaches to generate an array containing n number of non-repeating random numbers.
- Using do-while loop and includes() Method.
- Using a set and checking its size
Method 1: Using do-while loop and includes() Method
Here, the includes() function checks if an element is present in the array or not.
Example:
JavaScript
// You can take this value from user const n = 5 // Initial empty array const arr = []; // Null check if (n == 0) {
console.log( null )
} do {
// Generating random number
const randomNumber = Math
.floor(Math.random() * 100) + 1
// Pushing into the array only
// if the array does not contain it
if (!arr.includes(randomNumber)) {
arr.push(randomNumber);
}
} while (arr.length < n);
// Printing the array elements console.log(arr) |
Output
[ 29, 36, 38, 83, 50 ]
Time complexity:
O(n2)
Method 2: Using a set and checking its size
Remember that a set does not allow duplicate elements.
Example:
JavaScript
// You can take this value from user const n = 5 // Initial empty array const arr = []; // Null Check if (n == 0) {
console.log( null )
} let randomnumbers = new Set, ans;
// We keep adding elements till // size of set is equal to n while (randomnumbers.size < n) {
// Generating random number
// and adding it
randomnumbers.add(Math.floor(
Math.random() * 100) + 1);
} // Copying set elements into // the result array ans = [...randomnumbers]; // Printing the array console.log(ans) |
Output
[ 41, 75, 57, 62, 92 ]
Time complexity:
O(n)