Question

Is there any way in php wherein I can get n level keys for multi-dimensional array in php ?

Here is my associative array and as output I want an array which would contain all the values for keys object_id as you can there from the structure itself there are many nested levels for object_id and so how can I get all the values for keys object_id ?

   array
  'cart' => 
    array
      12061 => 
        array
          'object_id' => string '12061' (length=5)
          'discriminator' => string 'SimpleProductOffering' (length=21)
          'spec' => 
            array
              100012061 => 
                array
                  'object_id' => string '100012061' (length=9)
                  'discriminator' => string 'CompositeProductSpecification' (length=29)
                  'trait' => 
                    array
                      'MAIN_CPE' => 
                        array
                          'object_id' => string '1000000000015' (length=13)
                          'is_configurable' => string '0' (length=1)
                          'trait_value' => 
                            array
                              10001 => 
                                array
                                  'object_id' => string '10001' (length=5)
                                  'collateral' => 
                                    array
                                      empty
                          'collateral' => 
                            array
                              empty
          'offer_type' => null
          'price' => 
            array
              12862 => 
                array
                  'object_id' => string '12862' (length=5)
                  'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                  'price_alteration' => 
                    array
                      empty
                  'collateral' => 
                    array
                      empty
              12876 => 
                array
                  'object_id' => string '12876' (length=5)
                  'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                  'price_alteration' => 
                    array
                      0 => string '12876' (length=5)
                      1 => string '12894' (length=5)
                  'collateral' => 
                    array
                      empty
          'contained_offers' => 
            array
              empty
          'family' => 
            array
              0 => string 'TV Subscription' (length=24)
          'relationship' => 
            array
              'CHILDREN' => 
                array
                  'object_id' => string '1206102000' (length=10)
                  'min' => string '0' (length=1)
                  'max' => string '1000000' (length=7)
                  'related_offer' => 
                    array
                      0 => string '10410' (length=5)
                      1 => string '10411' (length=5)
              'REQUIREMENTS' => 
                array
                  'object_id' => string '1206104000' (length=10)
                  'min' => string '1' (length=1)
                  'max' => string '1' (length=1)
                  'related_offer' => 
                    array
                      0 => string '11950' (length=5)
                      1 => string '11990' (length=5)
              'EXCLUSIONS' => 
                array
                  'object_id' => string '1206101000' (length=10)
                  'min' => string '1' (length=1)
                  'max' => string '1' (length=1)
                  'related_offer' => 
                    array
                      0 => string '12062' (length=5)
                      1 => string '12063' (length=5)
              'ALTERNATIVES' => 
                array
                  'object_id' => string '1206105000' (length=10)
                  'min' => string '1' (length=1)
                  'max' => string '1' (length=1)
                  'related_offer' => 
                    array
                      0 => string '12263' (length=5)
              'BUNDLE_ITEMS' => 
                array
                  'object_id' => string '1206106000' (length=10)
                  'min' => string '1' (length=1)
                  'max' => string '1' (length=1)
                  'related_offer' => 
                    array
                      0 => string '12062' (length=5)
          'financial_terms' => 
            array
              'billing_period' => 
                array
                  0 => string 'QUARTERLY' (length=9)
              'payment_method' => 
                array
                  0 => string 'DIRECT_DEBIT' (length=12)
              'bill_presentation' => 
                array
                  0 => string 'PAPER' (length=5)
          'contract_constraints' => 
            array
              'min_contract_period' => int 24
              'cancellation_period' => string 'ALWAYS' (length=6)
              'notice_period' => int 3
              'rollover_period' => int 2
              'right_of_wd_period' => int 1
          'collateral' => 
            array
              empty
      10017 => 
        array
          'object_id' => string '10017' (length=5)
          'spec' => 
            array
              100010017 => 
                array
                  'object_id' => string '100010017' (length=9)
                  'discriminator' => string 'CompositeProductSpecification' (length=29)
                  'trait' => 
                    array
                      empty
          'offer_type' => null
          'price' => 
            array
              300306 => 
                array
                  'object_id' => string '300306' (length=6)
                  'price_alteration' => 
                    array
                      empty
                  'collateral' => 
                    array
                      empty
              12894 => 
                array
                  'object_id' => string '12894' (length=5)
                  'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                  'price_alteration' => 
                    array
                      empty
                  'collateral' => 
                    array
                      empty
              12862 => 
                array
                  'object_id' => string '12862' (length=5)
                  'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                  'price_alteration' => 
                    array
                      empty
                  'collateral' => 
                    array
                      empty
              12876 => 
                array
                  'object_id' => string '12876' (length=5)
                  'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                  'price_alteration' => 
                    array
                      0 => string '12876' (length=5)
                      1 => string '12894' (length=5)
                  'collateral' => 
                    array
                      empty
          'contained_offers' => 
            array
              0 => null
          'family' => 
            array
              empty
          'relationship' => 
            array
              'EXCLUSIONS' => 
                array
                  'object_id' => string '1001701000' (length=10)
                  'min' => string '1' (length=1)
                  'max' => string '1' (length=1)
                  'related_offer' => 
                    array
                      0 => string '11893' (length=5)
                      14 => string '12305' (length=5)
                      15 => string '12306' (length=5)
          'financial_terms' => 
            array
              'billing_period' => 
                array
                  0 => string 'MONTHLY' (length=7)
                  1 => string 'QUARTERLY' (length=9)
              'payment_method' => 
                array
                  0 => string 'DIRECT_DEBIT' (length=12)
                  1 => string 'DIRECT_DEBIT' (length=12)
              'bill_presentation' => 
                array
                  0 => string 'EMAIL' (length=5)
                  1 => string 'PAPER' (length=5)
          'contract_constraints' => 
            array
              'min_contract_period' => int 24
              'cancellation_period' => string 'ALWAYS' (length=6)
              'notice_period' => int 3
              'rollover_period' => int 2
              'right_of_wd_period' => int 1
          'collateral' => 
            array
              empty
  0 => 
    array
      11990 => 
        array
          'object_id' => string '11990' (length=5)
          'discriminator' => string 'SimpleProductOffering' (length=21)
          'spec' => 
            array
              100011990 => 
                array
                  'object_id' => string '100011990' (length=9)
                  'discriminator' => string 'CompositeProductSpecification' (length=29)
                  'trait' => 
                    array
                      empty
          'offer_type' => null
          'price' => 
            array
              12862 => 
                array
                  'object_id' => string '12862' (length=5)
                  'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                  'price_alteration' => 
                    array
                      empty
                  'collateral' => 
                    array
                      empty
              12876 => 
                array
                  'object_id' => string '12876' (length=5)
                  'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                  'price_alteration' => 
                    array
                      10017 => 
                        array
                          'object_id' => string '10017' (length=5)
                          'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                          'price_alteration' => 
                            array
                              empty
                          'collateral' => 
                            array
                              empty
                      12894 => 
                        array
                          'object_id' => string '12894' (length=5)
                          'discriminator' => string 'RecurringChargeProdOfferPriceCharge' (length=35)
                          'price_alteration' => 
                            array
                              empty
                          'collateral' => 
                            array
                              empty
                  'collateral' => 
                    array
                      empty
          'contained_offers' => 
            array
              empty
          'family' => 
            array
              0 => string 'CATV' (length=4)
          'relationship' => 
            array
              empty
          'financial_terms' => 
            array
              'billing_period' => 
                array
                  0 => string 'QUARTERLY' (length=9)
              'payment_method' => 
                array
                  0 => string 'DIRECT_DEBIT' (length=12)
              'bill_presentation' => 
                array
                  0 => string 'PAPER' (length=5)
          'contract_constraints' => 
            array
              'min_contract_period' => int 24
          'collateral' => 
            array
              empty

Output should be an array which would contain all the values for keys = object_id. Kindly advise ?

Answer 1

Dereleased’s solution will be faster I guess (as it uses internal loops), mine can also deal with array values for object_id keys. Your tradeoff 😉

---

function find_all($needle, array $haystack, array &$result = null) {
    // This is to initialize the result array and is only needed for
    // the first call of this function
    if(is_null($result)) {
        $result = array();
    }
    foreach($haystack as $key => $value) {
        // Check whether the key is the value we are looking for. If the value
        // is not an array, add it to the result array.
        if($key === $needle && !is_array($value)) {
            $result[] = $value;
        }
        if(is_array($value)) {
            // If the current value is an array, we perform the same
            // operation with this 'subarray'.
            find_all($needle, $value, $result);
        }
    }
    // This is only needed in the first function call to retrieve the results
    return $result;
}

As you can see, the result array is given to every call of the function as reference (denoted by the &). This way, every recursive call of this function has access to the same array and can just add a find.

You can do:

$values = find_all('object_id', $array);

It gives me for your array:

Array
(
    [0] => 12061
    [1] => 100012061
    [2] => 1000000000015
    [3] => 10001
    [4] => 12862
    [5] => 12876
    [6] => 1206102000
    [7] => 1206104000
    [8] => 1206101000
    [9] => 1206105000
    [10] => 1206106000
    [11] => 10017
    [12] => 100010017
    [13] => 300306
    [14] => 12894
    [15] => 12862
    [16] => 12876
    [17] => 1001701000
    [18] => 11990
    [19] => 100011990
    [20] => 12862
    [21] => 12876
    [22] => 10017
    [23] => 12894
)