为什么我的数组变量在循环中填充时是空的？[副本]

Question

$crawler = new Crawler($xml);

$parkList = []; 

$crawler->filter('wfs|FeatureCollection > gml|featureMember > bm|ST_PARK_P > bm|NOM')->each(function (Crawler $actualPark, $i) {
        $parkList[$i] = [];
        $parkList[$i][] = $actualPark->text();
        //var_dump($parkList); // $parklist variable is filled
});

$crawler->filter('wfs|FeatureCollection > gml|featureMember > bm|ST_PARK_P > bm|geometry > gml|Point > gml|pos')->each(function (Crawler $actualPark, $i) {
        $parkList[$i][] = explode(' ', $actualPark->text())[0];
});
$crawler->filter('wfs|FeatureCollection > gml|featureMember > bm|ST_PARK_P > bm|geometry > gml|Point > gml|pos')->each(function (Crawler $actualPark, $i) {
        $parkList[$i][] = explode(' ', $actualPark->text())[1];
});


return $parkList; //parklist variable is strangely empty

为什么我的parkList变量在.each函数外是空的，而我在循环外声明了它并在循环期间填充了它的值...并且循环成功执行？

Answer 1

您正在使用一个闭包，因此需要使用use方法...函数（Crawler$actualPark,$I)使用($parklist)

$crawler = new Crawler($xml);

$parkList = []; 

$crawler->filter('wfs|FeatureCollection > gml|featureMember > bm|ST_PARK_P > bm|NOM')->each(function (Crawler $actualPark, $i) use ($parkList) {
        $parkList[$i] = [];
        $parkList[$i][] = $actualPark->text();
        //var_dump($parkList); // $parklist variable is filled
});

//var_dump($parkList); // $parklist variable will now be filled