TermFrequency extension for php-nlp-tools

TermFrequency.php

<?php

namespace App\Library;

use NlpTools\Analysis\FreqDist;


class TermFrequency extends FreqDist
{

    const FREQUENCY_MODE = 1;
    const BOOLEAN_MODE = 2;
    const LOGARITHMIC_MODE = 3;
    const AUGMENTED_MODE = 4;
    const COUNT_MODE = 5;
  
    public function __construct(array $tokens, $mode=self::FREQUENCY_MODE)
    {
        parent::__construct($tokens);
        $this->mode = $mode;
    }


    public function getTf($term)
    {
        $count = $this->getTotalByToken($term);
        if(!$count) {
            return 0;
        } else {
            switch($this->mode) { 
                case self::BOOLEAN_MODE:
                    return 1;
                case self::LOGARITHMIC_MODE:
                    return  (1 + log($count));
                case self::AUGMENTED_MODE:
                    return 0.5 + (0.5 * ($count / current($this->getKeyValues())));
                case self::COUNT_MODE:
                    return $this->getTotalByToken($term);
                case self::FREQUENCY_MODE:
                default:
                    return $count/$this->getTotalTokens();
            }
        }    

    }


}