Clash Royale CLAN TAG#URR8PPP

Function to count duplicate characters in a string

I am trying to write a function which finds all unique characters in a provided string.

I'd like the function to return the results in the following format:

removeDuplicates('th#elex_ash?') -> unique: 'aehlstx', duplicates: 2


So far I have come up with the following attempted solution:

function removeDuplicates(str)
var unique ="";
for (var i=0; i<str.length; i++)
if(unique.indexOf(str[i]) == -1)
unique += str[i];


unique = unique.replace(/[&/\#,_+()$~%.'":*?<>]/g, '');
return unique.split('').sort().join('');






console.log(removeDuplicates('aaabbbac'));
console.log(removeDuplicates('a'));
console.log(removeDuplicates('th#elex_ash?'));


3 Answers
3

If you are writing for an environment where you can use newer javascript features. Set makes this a little easier since it will enforce uniqueness among the contents. You can also compare the lengths of the cleaned string with the uniques to find the duplicate count

Set

For example:

function removeDuplicates(str)
str = str.replace(/[&/\#,_+()$~%.'":*?<>]/g, '')
let unique = Array.from(new Set(str))
.sort((a, b) => a.localeCompare(b))
.join('')

let duplicates = str.length - unique.length
return unique, duplicates


console.log(removeDuplicates("th#elex_ash?"))

function removeDuplicates(str)
var returnObject =
unique : "",
duplicates : 0
;

for (var i = 0; i < str.length; i++)
if (returnObject.unique.indexOf(str[i]) < 0)
returnObject.unique += str[i];
else
returnObject.duplicates++;



returnObject.unique = returnObject.unique.replace(/[&/\#,_+()$~%.'":*?<>]/g, '');
returnObject.unique = returnObject.unique.split('').sort().join('');

return returnObject;


console.log(removeDuplicates('aaabbbac'));
console.log(removeDuplicates('a'));
console.log(removeDuplicates('th#elex_ash?'));


unique

uniques

You are very close!

An object can be returned in Javascript just like anything else; for instance, to return the format you were asking for, simply do the following:

return
unique: unique,
duplicates: duplicates



Notice how your variable names are the same as your property keys? You can use a shorthand notation by simply writing unique and duplicates, rather than unique: unique and duplicates: duplicates.

unique

duplicates

unique: unique

duplicates: duplicates

You're not keeping a count of duplicates. To do so, simply add an else block to your if(unique.indexOf(str[i]) == -1) conditional, which should only be reached when a character is indeed a duplicate, and increment a counter - lets name it duplicates.

else

if(unique.indexOf(str[i]) == -1)

duplicates

Complete Solution

function removeDuplicates(str)
var unique = "";
var duplicates = 0;

for (var i = 0; i < str.length; i++)
if (unique.indexOf(str[i]) == -1)
unique += str[i];
else
duplicates++;


unique = unique.replace(/[&/\#,_+()$~%.'":*?<>]/g, '').split('').sort().join('')

return
unique,
duplicates




const testString = 'th#elex_ash?';
const expectedOutput =
unique: 'aehlstx',
duplicates: 2
;

console.log(removeDuplicates(testString));

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