CODEWITHSUNDEEP
javascriptalgorithm
ManuKaracho
ManuKaracho

Reputation: 1218

Algorithm for counting occurrences of words in string

I am trying to build an algorithm to see, which words occurr the most in comments.

Therefore I came up with this (in Javascript):

var analyze = function(comments){
    var detectedWords = [];
    var result = {};
    comments.forEach(function(comment){
        var words = comment.message.split(" ");
        words.forEach(function(word){
            word = word.toLowerCase();
            if(word !== ""){
                if(detectedWords.indexOf(word) === -1){
                    detectedWords.push(word);
                    result[detectedWords.indexOf(word)] = {"name":word,"count":1};
                }else{
                    result[detectedWords.indexOf(word)].count++;
                }
            }
        });
    });

    return _.orderBy(result, ['count'], ['desc']);
}

Can the algorithm be optimized further? (toLowerCase() outside the inner loop?

In next step I would define a "blacklist" or words that are not interesting like "the, is, I, am, are,..."

Upvotes: 2

Views: 1189

Answers (1)

Nina Scholz
Nina Scholz

Reputation: 386560

You could use a hash table for reference to the array item for a faster access to the count object. result is now an array, which is now sortable.

var analyze = function (comments) {
    var result = [],
        hash = {};
    comments.forEach(function (comment) {
        var words = comment.message.split(" ");
        words.forEach(function (word) {
            word = word.toLowerCase();
            if (word !== "") {
                if (!hash[word]) {
                    hash[word] = { name: word, count: 0 };
                    result.push(hash[word]);
                }
                hash[word].count++;
            }
        });
    });

    return result.sort(function (a, b) { return b.count - a.count;});
    //return _.orderBy(result, ['count'], ['desc']);
}

console.log(analyze([{ message: 'a b c d a v d e f g q' }]));

Upvotes: 1

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