从多维关联数组php通过键动态获取值

Question

iam getting "undefined index error" when trying to get the numeric value dynamically.

if have an array like this,

$area =  array( 
    'MetroManila' => array ('Manila'=>'133900000', 'Mandaluyong'=>'137401000', 'Marikina'=>'137402000'),
    'Bataan' =>array('Abucay'=>'030801000', 'Bagac'=>'030802000', 'Balanga'=>'030803000', ),
);

all i want to get is to get the numeric value from array like this "137401000"

when i do it like echo $area['MetroManila'][Mandaluyong]; its okay. but when i get the value dynamically $area[$var][$var]; it returns an undefined index error.

i have already check the value of $var and no problem with its value.

Answer 1

You need two different variables, one for the first dimension, another for the second dimension. Eg

$province = 'MetroManila';  
$city = 'Mandaluyong'; 
echo $area[$province][$city];

Answer 2

You have to make recursive usage of a function like this

$area =  array( 
   'MetroManila' => array ('Manila'=>'133900000', 
'Mandaluyong'=>'137401000', 'Marikina'=>'137402000'),
'Bataan' =>array('Abucay'=>'030801000', 'Bagac'=>'030802000', 'Balanga'=>'030803000', ),
);
$arr=[];
 array_walk_recursive(
      $area, 
      function($k) use (&$arr) {
           $arr[]=$k;
       }
 );
print_r($arr);