考虑在此JSON对象中表达的以下(相当复杂的)查询：

{
    "name": "Kindle Fire",
    "sale": true,
    "price": {
        "$gt": 199,
        "$lt": 264
    },
    "price.vat": { // bogus, just to show $a['price.vat'] == $a['price']['vat']
        "$lte": 1.2
    },
    "$or": {
        "qty": {
            "$gt": 30
        },
        "eta": {
            "$or": {
                "$lt": 3,
                "$gt": 30
            }
        }
    },
    "countriesAvailable": {
        "$in": [
            "US",
            "CA"
        ]
    }
}

目的

我想解析那个JSON,以便它计算到PHP的等价物(其中$a是我的目标数据)：

$a['name'] == 'Kindle Fire' &&
$a['sale'] == true &&
(
    $a['price'] > 199 && $a['price'] < 264
) &&
$a['price']['vat'] <= 1.2 &&
(
    $a['qty'] > 30 ||
    (
        $a['eta'] < 3 || $a['eta'] > 30
    )
) &&
in_array($a['countriesAvailable'], array('US', 'CA'))

我几乎没有构建表达式评估程序的经验.我的想法是从最内层到最外层遍历查询,根据需要调用相应的MongoDB operator方法.

假设$a匹配查询,这将是评估计划：

$query = array();
$query['name'] = true;
$query['sale'] = true;
$query['price'] = array();
$query['price']['$gt'] = true;
$query['price']['$lt'] = true;
$query['price']['vat'] = array();
$query['price']['vat']['$lte'] = true;
$query['$or'] = array();
$query['$or']['qty'] = array();
$query['$or']['qty']['$gt'] = false;
$query['$or']['eta'] = array();
$query['$or']['eta']['$or'] = array();
$query['$or']['eta']['$or']['$lt'] = true;
$query['$or']['eta']['$or']['$gt'] = false;
$query['countriesAvailable'] = array();
$query['countriesAvailable']['$in'] = true;

第二步：

$query = array();
$query['name'] = true;
$query['sale'] = true;
$query['price'] = array();
$query['price']['$gt'] = true;
$query['price']['$lt'] = true;
$query['price']['vat'] = true;
$query['$or'] = array();
$query['$or']['qty'] false;
$query['$or']['eta'] = array();
$query['$or']['eta']['$or'] true;
$query['countriesAvailable'] = true;

第三步：

$query = array();
$query['name'] = true;
$query['sale'] = true;
$query['price'] = true;
$query['$or'] = array();
$query['$or']['qty'] false;
$query['$or']['eta'] true;
$query['countriesAvailable'] = true;

第四步：

$query = array();
$query['name'] = true;
$query['sale'] = true;
$query['price'] = true;
$query['$or'] = true;
$query['countriesAvailable'] = true;

由于所有值都是布尔值,因此评估结束返回！in_array(false,$query,true).

如果存在更好的方法,请告诉我.

问题：访问父阵列键

我试图获得最里面的元素和相关(忽略运算符)数组索引路径,例如,如果我使用RecursiveIteratorIterator,我得到第一次迭代的正确值：

$nodes = new ArrayIterator($query);
$iterator = new RecursiveArrayIterator($nodes);
$iteratorIterator = new RecursiveIteratorIterator($iterator, RecursiveIteratorIterator::LEAVES_ONLY);

print_r(iterator_to_array($iteratorIterator));

Array
(
    [name] => Kindle Fire HD
    [sale] => 1
    [$gt] => 30
    [$lt] => 3
    [$lte] => 1.2
    [0] => US
    [1] => CA
)

但是,由于我无法确定密钥所指的是什么$index,更不用说密钥值被后面的条目覆盖以及我无法更改其值的事实,因此它没什么用处.

我也试过玩RecursiveArrayIterator,但是没有hasParent()/ getParent()方法,它似乎没有给我带来太多的优势,而不仅仅是简单地预测数组.

有什么建议么？

解决方法:

我很快就读到你的问题,听起来你想要访问叶子并知道它们的关键路径.

所以在这里：

$ritit = new RecursiveIteratorIterator(new RecursiveArrayIterator($myArray));
foreach ($ritit as $leafValue) {
    $keyPath = array();
    foreach (range(0, $ritit->getDepth()) as $depth) {
        $keyPath[] = $ritit->getSubIterator($depth)->key();
    }
    // do something with $keyPath


    // or
    $hasParent = $ritit->getDepth() > 0;
    $parentIter = $ritit->getSubIterator($ritit->getDepth() - 1);
    $parentKey = $parentIter->key();
}