66 lines
1.4 KiB
PHP
66 lines
1.4 KiB
PHP
<?php
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declare(strict_types=1);
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namespace Phpml\Math\Statistic;
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use Phpml\Exception\InvalidArgumentException;
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class Mean
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{
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/**
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* @throws InvalidArgumentException
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*/
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public static function arithmetic(array $numbers): float
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{
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self::checkArrayLength($numbers);
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return array_sum($numbers) / count($numbers);
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}
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/**
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* @return float|mixed
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*
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* @throws InvalidArgumentException
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*/
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public static function median(array $numbers)
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{
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self::checkArrayLength($numbers);
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$count = count($numbers);
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$middleIndex = (int) floor($count / 2);
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sort($numbers, SORT_NUMERIC);
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$median = $numbers[$middleIndex];
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if ($count % 2 === 0) {
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$median = ($median + $numbers[$middleIndex - 1]) / 2;
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}
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return $median;
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}
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/**
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* @return mixed
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*
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* @throws InvalidArgumentException
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*/
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public static function mode(array $numbers)
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{
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self::checkArrayLength($numbers);
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$values = array_count_values($numbers);
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return array_search(max($values), $values, true);
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}
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/**
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* @throws InvalidArgumentException
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*/
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private static function checkArrayLength(array $array): void
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{
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if (count($array) === 0) {
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throw new InvalidArgumentException('The array has zero elements');
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}
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}
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}
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