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<?php |
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namespace PierceMcGeough\phpquartiles; |
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class Quartile |
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{ |
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private $scores; |
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private $quartiles; |
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/** |
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* Create a new Quartiles Instance |
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* @param array $scores |
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*/ |
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public function __construct(array $scores) |
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{ |
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$this->scores = $scores; |
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if (!$this->arrayOnlyContainsNumbers()) { |
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throw new \Exception('Scores can only contain numbers'); |
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} |
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$this->calculateQuartiles(); |
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} |
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/** |
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* Calculate the quartiles |
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*/ |
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private function calculateQuartiles() |
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{ |
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if (count($this->scores)+1 <= 3) { |
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return; |
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} |
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sort($this->scores, SORT_NUMERIC); |
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$this->quartiles = [ |
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'first' => $this->getQuartile(0.25), |
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'second' => $this->getQuartile(0.50), |
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'third' => $this->getQuartile(0.75) |
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]; |
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} |
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/** |
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* Get the quartiles |
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* |
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* @return array|void |
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*/ |
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public function getAllQuartiles() |
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{ |
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return $this->quartiles; |
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} |
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/** |
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* @return numeric |
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*/ |
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public function getFirstQuartile() |
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{ |
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return $this->getQuartile(0.25); |
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} |
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/** |
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* @return numeric |
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*/ |
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public function getSecondQuartile() |
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{ |
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return $this->getQuartile(0.50); |
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} |
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/** |
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* @return numeric |
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*/ |
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public function getMedianQuartile() |
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{ |
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return $this->getQuartile(0.50); |
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} |
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/** |
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* @return numeric |
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*/ |
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public function getThirdQuartile() |
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{ |
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return $this->getQuartile(0.75); |
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} |
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/** |
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* Use the params to work out the quartile specific to this $array |
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* |
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* @param double $quartilePlace |
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* @return float |
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*/ |
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public function getQuartile($quartilePlace) |
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{ |
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$pos = (count($this->scores) + 1) * $quartilePlace; |
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if (fmod($pos, 1) == 0) { |
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return $this->scores[$pos-1]; |
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} |
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$fraction = $pos - floor($pos); |
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$lower_num = $this->scores[floor($pos) - 1]; |
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$upper_num = $this->scores[ceil($pos) - 1]; |
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$difference = $upper_num - $lower_num; |
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return round($lower_num + ($difference * $fraction), 2); |
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} |
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/** |
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* Validate that the scores array only contains numbers |
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* |
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* @return boolean |
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*/ |
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private function arrayOnlyContainsNumbers() |
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{ |
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foreach ($this->scores as $score) { |
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if (!is_numeric($score)) { |
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return false; |
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} |
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} |
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return true; |
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} |
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} |
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PierceMcGeough /
phpquartiles
