[FIXED] Dynamically extract only certain keys from an array

Issue

I need to dynamically extract only certain keys from an array.

Ex:

$array = [
        "a" => true,
        "b" => false,
        "c" => [
            0 => [
                "a" => "x",
                "b" => [
                    "x" => "Y"
                ]
            ],
            1 => [
                "a" => "x",
                "b" => [
                    "x" => "Y"
                ]
            ],
        ]
    ];

And from it I need to extract the following array, which can change:

$newArray = [
        "b" => false,
        "c" => [
            0 => [
                "b" => [
                    "x" => "Y"
                ]
            ],
            1 => [
                "b" => [
                    "x" => "Y"
                ]
            ],
        ]
    ];

Solution

this might by easy with the following recursive function:

<?php
$array = [
            "a" => true,
            "b" => false,
            "c" => [
                0 => [
                    "a" => "x",
                    "b" => [
                        "x" => "Y"
                    ]
                ],
                1 => [
                    "a" => "x",
                    "b" => [
                        "x" => "Y"
                    ]
                ],
            ]
        ];

$cleaned_array = unset_by_key($array,"a");    
$extracted_array = arrayRecursiveDiff ($array, $cleaned_array);

print_r($cleaned_array);  
print_r($extracted_array);

function unset_by_key ($arr,$nkey) {
  unset($arr[$nkey]);
  foreach ($arr as $key=>$val) {
    if (is_array($val)) {
        $arr[$key] = unset_by_key($val,$nkey);
    }
  }
  return $arr;
}

// THX TO: https://stackoverflow.com/questions/3876435/recursive-array-diff
function arrayRecursiveDiff($aArray1, $aArray2) {
  $aReturn = array();

  foreach ($aArray1 as $mKey => $mValue) {
    if (array_key_exists($mKey, $aArray2)) {
      if (is_array($mValue)) {
        $aRecursiveDiff = arrayRecursiveDiff($mValue, $aArray2[$mKey]);
        if (count($aRecursiveDiff)) { $aReturn[$mKey] = $aRecursiveDiff; }
      } else {
        if ($mValue != $aArray2[$mKey]) {
          $aReturn[$mKey] = $mValue;
        }
      }
    } else {
      $aReturn[$mKey] = $mValue;
    }
  }
  return $aReturn;
} 

?>

Answered By - MatWer