How to usea Single Loop in Javascript
For all loops, it iterates over iterable data structures and gives the element in each iteration, and in each iteration, we are checking that a particular element has another last index or not; if it has another last index, it’s a duplicated element.
Example: Below code will illustrate the approach.
let check_duplicate_in_array = (input_array) => {
let duplicate_elements = [];
for (element of input_array) {
if (input_array.indexOf(element)
!== input_array.lastIndexOf(element)) {
duplicate_elements.push(element);
}
}
return [...new Set(duplicate_elements)];
};
let arr = [1, 1, 2, 2, 3, 3, 4, 5, 6, 1];
console.log(check_duplicate_in_array(arr));
Output
[ 1, 2, 3 ]
JavaScript Program to Find Duplicate Elements in an Array
We are going to learn how can we Find Duplicate Elements in an Array. Finding duplicate elements in an array means identifying and listing any values that appear more than once within the array, helping to detect and manage redundant data or repeated elements within a collection of items.
There are several methods that can be used to find duplicate elements in an array by using JavaScript, which are listed below:
Table of Content
- Approach 1: Using Nested For In Loop
- Approach 2: Using Sort() Method
- Approach 3: Using filter() Method
- Approach 4: Using a Single Loop
- Approach 5: Using a Set
- Approach 6: Using Reduce Method
- Approach 7: Using indexOf() method
- Approach 8: Using an Object to Track Frequencies