Question

186

Regex remove repeated characters from a string by javascript

rated 0 times [ 190] [ 4] / answers: 1 / hits: 40944 / 11 Years ago, thu, october 10, 2013, 12:00:00

I have found a way to remove repeated characters from a string using regular expressions.

function RemoveDuplicates() {

    var str = aaabbbccc;

    var filtered = str.replace(/[^ws]|(.)1/gi, );  

    alert(filtered);

}

Output: abc
this is working fine.

But if str = aaabbbccccabbbbcccccc then output is abcabc.
Is there any way to get only unique characters or remove all duplicates one?
Please let me know if there is any way.

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michaelashelbieh

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3 Years ago

answered 11 Years ago kinsley · Accepted Answer

A lookahead like this, followed by something and this:

var str = aaabbbccccabbbbcccccc;

console.log(str.replace(/(.)(?=.*1)/g, )); // abc

Note that this preserves the last occurrence of each character:

var str = aabbccxccbbaa;

console.log(str.replace(/(.)(?=.*1)/g, )); // xcba

Without regexes, preserving order:

var str = aabbccxccbbaa;

console.log(str.split().filter(function(x, n, s) {

  return s.indexOf(x) == n

}).join()); // abcx