Remove duplicate characters from string

Question

I have to make a function in JavaScript that removes all duplicated letters in a string. So far I\'ve been able to do this: If I have the word \"anaconda\" it shows me as a

Answer 1

Method 1 : one Simple way with just includes JS- function

var data = 'sssssffffdffffdffffddfffffff';

    var ary = [];
    var item = '';
    for (const index in data) {
      if (!ary.includes(data[index])) {
        ary[index] = data[index];
        item += data[index];
      }
    }
    console.log(item);

Method 2 : Yes we can make this possible without using JavaScript function :

var name = 'sssssffffdffffdffffddfffffff';

let i = 0;
let newarry = [];

for (let singlestr of name) {
    newarry[i] = singlestr;
    i++;
}


// now we have new Array and length of string
length = i;

function getLocation(recArray, item, arrayLength) {

    firstLaction = -1;
    for (let i = 0; i < arrayLength; i++) {

        if (recArray[i] === item) {
            firstLaction = i;
            break;
        }

    }

    return firstLaction;

}


let finalString = '';
for (let b = 0; b < length; b++) {
   
    const result = getLocation(newarry, newarry[b], length);
    if (result === b) {
        finalString += newarry[b];
    }

}
console.log(finalString); // sdf

Answer 2

Here's what I used - haven't tested it for spaces or special characters, but should work fine for pure strings:

function uniquereduce(instring){ 
    outstring = ''
    instringarray = instring.split('')
    used = {}
    for (var i = 0; i < instringarray.length; i++) {
        if(!used[instringarray[i]]){
            used[instringarray[i]] = true
            outstring += instringarray[i]
        }
    }
    return outstring
}

Answer 3

This should work using Regex ;
NOTE: Actually, i dont know how this regex works ,but i knew its 'shorthand' , so,i would have Explain to you better about meaning of this /(.+)(?=.*?\1)/g;. this regex only return to me the duplicated character in an array ,so i looped through it to got the length of the repeated characters .but this does not work for a special characters like "#" "_" "-", but its give you expected result ; including those special characters if any

function removeDuplicates(str){
    var REPEATED_CHARS_REGEX = /(.+)(?=.*?\1)/g;
    var  res = str.match(REPEATED_CHARS_REGEX);
    var word = res.slice(0,1);
    var raw = res.slice(1);
    var together = new String (word+raw);
    var fer = together.toString();
    var length = fer.length;
    // my sorted duplicate;
      var result = '';
      for(var i = 0; i < str.length; i++) {
        if(result.indexOf(str[i]) < 0) {
          result += str[i];
        }
      }

      return {uniques: result,duplicates: length};
    } removeDuplicates('anaconda')

The regular expression /([a-zA-Z])\1+$/ is looking for:

([a-zA-Z]]) - A letter which it captures in the first group; then \1+ - immediately following it one or more copies of that letter; then $ - the end of the string. Changing it to /([a-zA-Z]).*?\1/ instead searches for:

([a-zA-Z]) - A letter which it captures in the first group; then .*? - zero or more characters (the ? denotes as few as possible); until \1 - it finds a repeat of the first matched character.

Answer 4

Using Set() and destructuring twice is shorter:

const str = 'aaaaaaaabbbbbbbbbbbbbcdeeeeefggggg';

const unique = [...new Set([...str])].join('');

console.log(unique);

Answer 5

console.log(("anaconda").split('').sort().join('').replace(/(.)\1+/g, ""));

By this, you can do it in one line.

output: 'cdo'

Answer 6

   function removeDuplicates(string){
      return string.split('').filter((item, pos, self)=> self.indexOf(item) == pos).join('');
   }

the filter will remove all characters has seen before using the index of item and position of the current element