How to find unique characters of a string in JavaScript ?
The purpose of this article is to find unique characters in a string using JavaScript.
Example:
Input: Geeksforgeeks Output: Geksforg Input: Geeksforgeeks is a great site for computer science Output: Geksforg Iaticmpun
To achieve this, we have the following approaches:
Approach 1: This is a naive approach to find the unique characters from a string. In this approach, we create a variable name uniq and we are iterating over the string using the for loop and at every iteration, we are checking if the uniq contains the character.
Javascript
<script>function findUnique(str){ // The variable that contains the unique values let uniq = ""; for(let i = 0; i < str.length; i++){ // Checking if the uniq contains the character if(uniq.includes(str[i]) === false){ // If the character not present in uniq // Concatenate the character with uniq uniq += str[i] } } return uniq;}console.log(findUnique("Geeksforgeeks"))console.log(findUnique("Geeksforgeeks Is a great site for computer science"))</script> |
Output:
"Geksforg" "Geksforg Iaticmpun"
Approach 2: In this method, we use the set data structure. The set data structure contains only unique values, and we take the advantage of it. So to extract the unique values from string using Set we follow the steps below.
- Using the split() method convert the string into an array.
- Create a Set using new Set() and pass the converted array into it.
- Now convert the set into an array using spread operator e.g: […set]
- And then join that array to make a string.
Javascript
<script>// Javascript program to extract unique characters from a stringfunction findUnique(str){ // Split the string to make array str = str.split("") // Create a set using array str = new Set(str); // Convert the set into array using spread // operator and join it to make string str = [...str].join(""); return str;}console.log(findUnique("Geeksforgeeks"))console.log(findUnique("Geeksforgeeks Is a great site for computer science"))</script> |
Output:
"Geksforg" "Geksforg Iaticmpun"
Approach 3: In this approach first, we convert the string into an array using the spread operator e.g. […str] and then we apply the reduce method on that array.
Javascript
<script>// Javascript program to extract unique characters from a stringfunction findUnique(str){ return [...str].reduce((acc, curr)=>{ return acc.includes(curr) ? acc : acc + curr; }, "")}console.log(findUnique("Geeksforgeeks"))console.log(findUnique("Geeksforgeeks Is a great site for computer science"))</script> |
Output:
"Geksforg" "Geksforg Iaticmpun"
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