php-ml/src/Phpml/Preprocessing/Imputer.php
2016-11-20 22:53:17 +01:00

100 lines
2.0 KiB
PHP

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