Using the existing key_exists array

Question

I’m trying to check if any value exists in an array in 1 array I can check if there is more when the array has another array inside I can’t verify if it exists.

1 array

$array = array("Volvo" => 'BMW', "BMW" => 'X5');

array (size=2)
  'Volvo' => string 'XC90' (length=4)
  'BMW' => string 'X5' (length=2)

result of 1 array

if (array_key_exists("Volvo",$array):                           
      echo "existe!";                           
  else :                            
      echo "não existe!";
  endif;

// resultado "existe"

2 array

$array = array(array('volvo' => 'XC90'), array('BMW' => 'X5'));

0 => 
    array (size=1)
      volvo' => string 'XC90' (length=4)
  1 => 
    array (size=1)
      'BMW' => string 'X5' (length=4)

result of 2 array

if (array_key_exists("Volvo",$array):                           
    echo "existe!";                           
else :                            
    echo "não existe!";
endif;


// resultado "não existe"

Answer 1

This is the expected behavior, there is no "Volvo" key in the initial array. If you have one array within the other (multidimensional array) you should check each array, just make a loop.

When you do:

$array = [['volvo' => 'XC90'], ['BMW' => 'X5']];

It’s the same as doing:

$array = [0 => ['volvo' => 'XC90'], 1 => ['BMW' => 'X5']];

So do: array_key_exists(1, $array); will return true, for these two cases above.

---

If you want to search the array key within another array you can do:

function multi_array_key_exists($key, array $array) : bool {
    // Pesquisamos no array atual:      
    if (array_key_exists($key, $array)) {
        return true;
    }

    foreach ($array as $v) {    

        // Chamamos a função novamente, para que ele continue a busca no array interno:
        if (is_array($v) && multi_array_key_exists($key, $v)) {
            return true;
        }
    }

    return false;
}

Answer 2

Response code in the OS^en: Check if specific array key exists in multidimensional array - PHP

function findKey($array, $keySearch)
{
    foreach ($array as $key => $item) {
        if ($key === $keySearch) {
            return true;
        } elseif (is_array($item) && findKey($item, $keySearch)) {
            return true;
        }
    }
    return false;
}

var_dump(findKey($array, 'Volvo'));

^{Note: This answer takes into account only if the searched value is equal to the searched.}

Answer 3

Hello, the solution to your problem is simpler than it looks. You should create a function that runs through the entire array (using the foreach) and check if that particular index is an array (for this we will use the function is_array), if the checked element is an array it calls the function again by passing that element as the main array. If not, it compares the verified element index to that passed value. See:

function verificaArray($array, $elemento){
    foreach ($array as $key => $value){
        if(!is_array($value)){ // verifica se elemento atual não é um array
            if($key === $elemento){ // se o elemento a ser procurado for igual ao do índice atual
                return true; // Se achou retorna true
            }else{
                end($array);

                if($key === key($array)){
                    return false; // se não acho e estiver no último elemento, retorna falso
                }
            }
        }else{
            return verificaArray ($value, $elemento); // Chama a função para fazer tudo de novo quando é array
        }
    }
}

$a = []; // seu array aqui 

if(verificaArray($a, "Volvo")){
    echo "Existe";
}else{
    echo "Não existe";
}

I hope I helped, hug!

Answer 4

To search for a given key of a multidimensional array it is necessary to use the recursion and function array_key_exists doesn’t do that.

function array_key_exists_recursive($needle, array $array)
{
    foreach ($array as $key => $value) {
        if ($key === $needle) return $value;
        if (is_array($value)) {
            if ($x = array_key_exists_recursive($key, $value)) return $x;
        }
    }
    return false;
}