What algorithm I need to find n-grams?

Question

What algorithm is used for finding ngrams?

Supposing my input data is an array of words and the size of the ngrams I want to find, what algorithm I should use?

Answer 1

EDIT: Sorry, this is PHP. I wasn't quite sure what you wanted. I don't know it in java but perhaps the following could be converted easily enough.

Well it depends on the size of the ngrams you want.

I've had quite a lot of success with single letters (especially accurate for language detection), which is easy to get with:

$letters=str_split(preg_replace('/[^a-z]/', '', strtolower($text)));
$letters=array_count_values($letters);

Then there is the following function for calculating ngrams from a word:

function getNgrams($word, $n = 3) {
        $ngrams = array();
        $len = strlen($word);
        for($i = 0; $i < $len; $i++) {
                if($i > ($n - 2)) {
                        $ng = '';
                        for($j = $n-1; $j >= 0; $j--) {
                                $ng .= $word[$i-$j];
                        }
                        $ngrams[] = $ng;
                }
        }
        return $ngrams;
}

The source of the above is here, which I recommend you read, and they have lots of functions to do exactly what you want.