JavaScript: Remove all characters from a given string that appear more than once

JavaScript Basic: Exercise-135 with Solution

Remove Characters Appearing More Than Once

Write a JavaScript program to remove all characters from a given string that appear more than once.

Visual Presentation:

Sample Solution:

JavaScript Code:

/**
 * Function to remove duplicate characters from a string
 * @param {string} str - The input string
 * @returns {string} - The string without duplicate characters
 */
function remove_duplicate_chars(str) {
  // Split the string into an array of characters
  var arr_char = str.split("");
  var result_arr = [];

  // Loop through each character of the array
  for (var i = 0; i < arr_char.length; i++) {
    // Check if the first and last occurrence of a character in the string are the same
    if (str.indexOf(arr_char[i]) === str.lastIndexOf(arr_char[i]))
      result_arr.push(arr_char[i]);
  }

  // Join the array of unique characters and return as a string
  return result_arr.join("");
}

console.log(remove_duplicate_chars("abcdabc"));
console.log(remove_duplicate_chars("python"));
console.log(remove_duplicate_chars("abcabc"));
console.log(remove_duplicate_chars("1365451"));

Output:

d
python

364

Live Demo:

See the Pen javascript-basic-exercise-135 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

/**
 * Function to remove duplicate characters from a string
 * @param {string} str - The input string
 * @returns {string} - The string without duplicate characters
 */
const remove_duplicate_chars = (str) => {
  // Split the string into an array of characters
  const arr_char = str.split("");
  const result_arr = [];

  // Loop through each character of the array
  for (let i = 0; i < arr_char.length; i++) {
    // Check if the first and last occurrence of a character in the string are the same
    if (str.indexOf(arr_char[i]) === str.lastIndexOf(arr_char[i]))
      result_arr.push(arr_char[i]);
  }

  // Join the array of unique characters and return as a string
  return result_arr.join("");
}

console.log(remove_duplicate_chars("abcdabc"));
console.log(remove_duplicate_chars("python"));
console.log(remove_duplicate_chars("abcabc"));
console.log(remove_duplicate_chars("1365451"));

For more Practice: Solve these Related Problems:

• Write a JavaScript program that removes all characters from a string that occur more than once, leaving only unique characters.
• Write a JavaScript function that builds a new string by filtering out characters with multiple occurrences in the original string.
• Write a JavaScript program that analyzes the frequency of each character and constructs a new string containing only single-occurrence characters.

Go to:

• JavaScript basic Exercises Home ↩
• JavaScript Exercises Home ↩

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