Filter CSV files in a quick'n'dirty way

csv.php

<?php
$dir = __DIR__;

function isValid($product) {
	return !empty($product[2]);
}

if (($productsFile = fopen($dir . '/products2.csv', "r")) !== FALSE) {
	$missingSkus = array_map('trim', file($dir . '/missing-images-sku.csv'));

	$outputOfMissingImages = fopen($dir . '/out/products-without-images.csv', 'w+');
	$errorsFile = fopen($dir . '/out/errors.csv', 'w+');

	// headers
	$fields = fgetcsv($productsFile, 1000, ",");
	$fieldsToKeep = array('sku', 'image', 'small_image', 'media_gallery', 'thumbnail');
	fputcsv($outputOfMissingImages, $fieldsToKeep);

	while (($product = fgetcsv($productsFile, 1000, ",")) !== FALSE) {
		if (count($product) == count($fields)) {
			$indexedProduct = array_combine($fields, $product);
			if (in_array($indexedProduct['sku'], $missingSkus)) {
				fputcsv($outputOfMissingImages, array_intersect_key($indexedProduct, array_flip($fieldsToKeep)));
			}
		} else {
			fputcsv($errorsFile, $product);
		}
	}

	fclose($productsFile);
	fclose($errorsFile);
	fclose($outputOfMissingImages);
}