JavaScript: Extract unique characters from a string

JavaScript Function: Exercise-16 with Solution

Extract Unique Characters

Write a JavaScript function to extract unique characters from a string.

Example string : "thequickbrownfoxjumpsoverthelazydog"
Expected Output : "thequickbrownfxjmpsvlazydg"

Sample Solution-1:

JavaScript Code:

// Define a function named unique_char that returns a string containing unique characters from the input string
function unique_char(str1) {
 // Create a variable str and initialize it with the input string
 var str = str1;
 // Create an empty string uniql to store unique characters
 var uniql = "";
 // Iterate through each character in the input string
 for (var x = 0; x < str.length; x++) { // Check if the current character is not already in the uniql string if (uniql.indexOf(str.charAt(x)) == -1) { // If true, append the current character to the uniql string uniql += str[x]; } } // Return the string containing unique characters return uniql; } // Log the result of calling unique_char with the input string "thequickbrownfoxjumpsoverthelazydog" to the console console.log(unique_char("thequickbrownfoxjumpsoverthelazydog")); 

Output:

thequickbrownfxjmpsvlazydg

Flowchart:

Live Demo:

See the Pen JavaScript - Extract unique characters from a string-function-ex- 16 by w3resource (@w3resource) on CodePen.

Sample Solution-2:

JavaScript Code:

// Function to extract unique characters from a string
function extractUniqueChars(inputString) {
 // Initialize an empty object to store unique characters
 const uniqueChars = {};
 // Iterate through each character in the input string
 for (let char of inputString) {
 // Add the character to the object as a key (objects cannot have duplicate keys)
 uniqueChars[char] = true;
 }
 // Join the keys of the object to form the result string of unique characters
 const resultString = Object.keys(uniqueChars).join('');
 return resultString;
}
// Example usage:
const inputString = "thequickbrownfoxjumpsoverthelazydog";
const result = extractUniqueChars(inputString);
// Log the result to the console
console.log(result);

Output:

thequickbrownfxjmpsvlazydg

Flowchart:

For more Practice: Solve these Related Problems:

• Write a JavaScript function that extracts unique characters from a string without using built-in methods like Set.
• Write a JavaScript function that returns the unique characters from a string in the order they first appear.
• Write a JavaScript function that extracts unique characters from a string while handling case sensitivity appropriately.
• Write a JavaScript function that extracts unique characters from a string and excludes any numeric digits.

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