PHP Apply multiple callback functions when using array_map, array_walk etc. functions

Question

I have encountered an array of serialized values like below:

Array
(
    [primary] => Array
        (
            [key_type_0_key_name] => a:1:{i:0;s:5:"27232";}
            [key_type_1_key_name] => a:1:{i:0;s:5:"27231";}
            [key_type_2_key_name] => a:1:{i:0;s:5:"27147";}
            [key_type_3_key_name] => a:1:{i:0;s:5:"27157";}
        )

    [additional] => Array
        (
            [key_type_0_key_othername] => a:1:{i:0;s:5:"27169";}
            [key_type_1_key_othername] => a:1:{i:0;s:5:"27160";}
            [key_type_2_key_othername] => a:1:{i:0;s:5:"27103";}
            [key_type_3_key_othername] => a:1:{i:0;s:5:"27149";}
        )
)

Now I need to apply two functions namely, unserialize and array_shift in specified order to extract the scalar values like 27169 and store in another array, how can I do that in one pass of array_map or I have to run array_map two times compulsorily ?

Also one problem is with recursion, only array_walk_recursive handles recursion properly, but in my case if I try below code, I am getting the given error:

return array_walk_recursive($array, function ( &$value ) {
        $value = array_shift( unserialize( $value ) );
    });

Error:

 Strict Standards: Only variables should be passed by reference in /path/to/file.php on line 367

Expected Result:

Array
(
    [primary] => Array
        (
            27232
            27231
            27147
            27157
        )

    [additional] => Array
        (
            27169
            27160
            27103
            27149
        )
)

Answer 1

With no calls to array_map.

<?php

$data = [
    'primary' =>
    [
        'a:1:{i:0;s:5:"27232";}',
        'a:1:{i:0;s:5:"27231";}',
        'a:1:{i:0;s:5:"27147";}',
        'a:1:{i:0;s:5:"27157";}'
    ],
    'additional' =>
    [
        'a:1:{i:0;s:5:"27169";}',
        'a:1:{i:0;s:5:"27160";}',
        'a:1:{i:0;s:5:"27103";}',
        'a:1:{i:0;s:5:"27149";}'
    ]
];



$numbers = [];
foreach($data as $key=>$value) {
    foreach($value as $k=>$v) {
        $unserialized = unserialize($v);
        $numbers[$key][] = (int) array_shift($unserialized);
    }
}

var_dump($numbers);

Output:

array (size=2)
  'primary' => 
    array (size=4)
      0 => int 27232
      1 => int 27231
      2 => int 27147
      3 => int 27157
  'additional' => 
    array (size=4)
      0 => int 27169
      1 => int 27160
      2 => int 27103
      3 => int 27149

Here a mutating array_walk example with three array_map calls. Far uglier and harder to read in my eyes, but each their own:

array_walk($data, function(&$v) {
        $v = array_map('intval', array_map('array_shift', array_map('unserialize', $v)));
    }
);
var_dump($data);

Output:

    array (size=2)
      'primary' => 
        array (size=4)
          0 => int 27232
          1 => int 27231
          2 => int 27147
          3 => int 27157
      'additional' => 
        array (size=4)
          0 => int 27169
          1 => int 27160
          2 => int 27103
          3 => int 27149