Remove occurrences of duplicate words in a string

Question

Take the following string as an example:

var string = \"spanner, span, spaniel, span\";

From this string I would like to find the duplicate

Answer 1

Both the other answers would work fine, although the filter array method used by PSL was added in ECMAScript 5 and won't be available in old browsers.

If you are handling long strings then using $.inArray/Array.indexOf isn't the most efficient way of checking if you've seen an item before (it would involve scanning the whole array each time). Instead you could store each word as a key in an object and take advantage of hash-based look-ups which will be much faster than reading through a large array.

var tmp={};
var arrOut=[];
$.each(string.split(', '), function(_,word){
    if (!(word in tmp)){
        tmp[word]=1;
        arrOut.push(word);
    }
});
arrOut.join(', ');