在PHP中检索多维数组的键值

Question

如何引用多维数组的键？这是数组:

Array
(
[Nov 18, 2011] => Array
    (
        [C] => 3
        [I] => 1
    )
[Nov 22, 2011] => Array
    (
        [C] => 2
    )
)

这是foreach循环:

foreach($array as $date) { 
    foreach ($date as $k=>$v) {         
        // how to I reference the value of $billdate here ?
    }            
} 

引用内部循环$k和$v内部循环很容易,但是如何引用外部循环中包含的日期值？ foreach foreach

谢谢您的帮助.

Answer 1

$billdate在外部foreach循环中为键指定一个值(显然命名).

foreach( $array as $billdate => $date) { 
    foreach( $date as $k => $v) {         
        echo $billdate; // Prints something like Nov 18, 2011
    }            
} 

Answer 2

假设$billdate是每个顶级数组的关键:

foreach ($array as $billdate => $date) {
    foreach ($date as $k => $v) {
        var_dump($billdate, $k, $v);
    }
}