88 lines
1.9 KiB
PHP
88 lines
1.9 KiB
PHP
<?php
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declare(strict_types=1);
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namespace Phpml\Preprocessing;
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use Phpml\Exception\InvalidOperationException;
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use Phpml\Preprocessing\Imputer\Strategy;
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class Imputer implements Preprocessor
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{
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public const AXIS_COLUMN = 0;
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public const AXIS_ROW = 1;
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/**
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* @var mixed
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*/
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private $missingValue;
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/**
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* @var Strategy
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*/
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private $strategy;
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/**
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* @var int
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*/
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private $axis;
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/**
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* @var mixed[]
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*/
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private $samples = [];
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/**
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* @param mixed $missingValue
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*/
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public function __construct($missingValue, Strategy $strategy, int $axis = self::AXIS_COLUMN, array $samples = [])
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{
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$this->missingValue = $missingValue;
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$this->strategy = $strategy;
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$this->axis = $axis;
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$this->samples = $samples;
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}
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public function fit(array $samples, ?array $targets = null): void
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{
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$this->samples = $samples;
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}
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public function transform(array &$samples, ?array &$targets = null): void
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{
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if ($this->samples === []) {
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throw new InvalidOperationException('Missing training samples for Imputer.');
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}
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foreach ($samples as &$sample) {
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$this->preprocessSample($sample);
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}
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}
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private function preprocessSample(array &$sample): void
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{
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foreach ($sample as $column => &$value) {
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if ($value === $this->missingValue) {
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$value = $this->strategy->replaceValue($this->getAxis($column, $sample));
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}
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}
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}
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private function getAxis(int $column, array $currentSample): array
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{
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if ($this->axis === self::AXIS_ROW) {
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return array_diff($currentSample, [$this->missingValue]);
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}
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$axis = [];
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foreach ($this->samples as $sample) {
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if ($sample[$column] !== $this->missingValue) {
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$axis[] = $sample[$column];
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}
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}
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return $axis;
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}
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}
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