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

JavaScript Basic: Exercise-135 with Solution

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

Pictorial Presentation:

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

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Remove all characters from a given string that appear more than once</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function remove_duplicate_cchars(str) {
  var arr_char = str.split("");
  var result_arr = [];

  for (var i = 0; i < arr_char.length; i++) {
    if (str.indexOf(arr_char[i]) === str.lastIndexOf(arr_char[i]))
      result_arr.push(arr_char[i]);
    }

  return result_arr.join("");
}
console.log(remove_duplicate_cchars("abcdabc"));
console.log(remove_duplicate_cchars("python"));
console.log(remove_duplicate_cchars("abcabc"));
console.log(remove_duplicate_cchars("1365451"));

Sample Output:

d
python

364

Flowchart:

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

ES6 Version:

function remove_duplicate_cchars(str) {
  const arr_char = str.split("");
  const result_arr = [];

  for (let i = 0; i < arr_char.length; i++) {
    if (str.indexOf(arr_char[i]) === str.lastIndexOf(arr_char[i]))
      result_arr.push(arr_char[i]);
    }

  return result_arr.join("");
}
console.log(remove_duplicate_cchars("abcdabc"));
console.log(remove_duplicate_cchars("python"));
console.log(remove_duplicate_cchars("abcabc"));
console.log(remove_duplicate_cchars("1365451"));

Live Demo:

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

Improve this sample solution and post your code through Disqus

Previous: Write a JavaScript program to change the characters (lower case) in a string where a turns into z, b turns into y, c turns into x, ..., n turns into m, m turns into n, ..., z turns into a.
Next: Write a JavaScript program to replace the first digit in a string (should contains at least digit) with $ character.

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JavaScript: Tips of the Day

Returns the sum of the powers of all the numbers from start to end (both inclusive)

Example:

const sumPower = (end, power = 2, start = 1) =>
  Array(end + 1 - start)
    .fill(0)
    .map((x, i) => (i + start) ** power)
    .reduce((a, b) => a + b, 0);
console.log(sumPower(10)); // 385
console.log(sumPower(10, 3)); // 3025
console.log(sumPower(10, 3, 5)); // 2925 

Output:

385
3025
2925