Question

我有一个recursivearray，它不返回特定数组结构中的对象/元素：

尝试使用递归的数组如下：

$feedStruct = [database] => Array
    (
        [property] => Array
            (
                [0] => Array
                    (
                        [title] => Array
                            (
                            )

                        [tipology] => Array
                            (
                            )

                        [description] => Array
                            (
                            )

                        [location] => Array
                            (
                            )

                        [year] => Array
                            (
                            )

                        [price] => Array
                            (
                            )

                        [area_plot] => Array
                            (
                            )

                        [habitable_area] => Array
                            (
                            )

                        [ref] => Array
                            (
                            )

                        [video] => Array
                            (
                            )

                        [default_photo] => Array
                            (
                            )

                        [photo1] => Array
                            (
                            )

                    )

                [1] => Array
                    (
                        [title] => Array
                            (
                            )

                        [tipology] => Array
                            (
                            )

                        [description] => Array
                            (
                            )

                        [location] => Array
                            (
                            )

                        [year] => Array
                            (
                            )

                        [price] => Array
                            (
                            )

                        [area_plot] => Array
                            (
                            )

                        [habitable_area] => Array
                            (
                            )

                        [ref] => Array
                            (
                            )

                        [video] => Array
                            (
                            )

                        [default_photo] => Array
                            (
                            )

                        [photo1] => Array
                            (
                            )

                    )

            )

    )

代码如下：

     $iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($feedStruct));
     $keys = array();
     foreach ($iterator as $key => $value) {
         // Build long key name based on parent keys
         for ($i = $iterator->getDepth() - 1; $i >= 0; $i--) {

          $val = $iterator->getSubIterator($i)->key();

          }
     }

当使用上面的数组运行它不会迭代，其他数组我没有问题，任何想法为什么？

谢谢

Answer 1

您的$iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($feedStruct));将被解释为$iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($feedStruct), RecursiveIteratorIterator::SELF_FIRST); ，因为RecursiveIteratorIterator::LEAVES_ONLY是三个中的默认参数（即RecursiveIteratorIterator::SELF_FIRST，RecursiveIteratorIterator::CHILD_FIRST）。

我会尝试解释参数。假设你有下面的数组

$array = array(
    0 => array(
        'city' => 'Jos',
        'places_to_visit' => array(
            'Lagos',
            'Capetown'
        )
    ),
    1 => "sd"
);
$iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($feedStruct), $mode);
$keys = array();
foreach ($iterator as $key => $value) {
// Build long key name based on parent keys
    for ($i = $iterator->getDepth() - 1; $i >= 0; $i--) {
        $val[] = $iterator->getSubIterator($i)->key();
    }
}

RecursiveIteratorIterator::LEAVES_ONLY表示仅迭代每个结构中的最后一个值。如果是上面的数组$array，请$mode = RecursiveIteratorIterator::LEAVES_ONLY，

print_r($val); 
/* Outputs
city => Jos
0 => Lagos
1 => Capetown
1 => sd */

RecursiveIteratorIterator::CHILD_FIRST表示在父母之前首先迭代子值。如果是上面的数组$array，请$mode = RecursiveIteratorIterator::CHILD_FIRST，

print_r($val); 
/* Outputs
city => Jos
0 => Lagos
1 => Capetown
places_to_visit => Array()
0 => Array()
1 => sd */

RecursiveIteratorIterator::SELF_FIRST表示在每个结构中首先仅迭代父值。如果是上面的数组$array，请$mode = RecursiveIteratorIterator::SELF_FIRST，

print_r($val); 
/*Outputs 
0 => Array()
city => Jos
places_to_visit => Array()
0 => Lagos
1 => Capetown
1 => sd */

在您的情况下，$iterator将返回 0 ，因为您的结构$feedStruct中没有叶子（最终值）。试试RecursiveIteratorIterator::SELF_FIRST，效果很好。

RecursiveIterator不返回任何对象

1 个答案: