php use array as keys code example

Example 1: php keys of array

$array = array(0 => 100, "cor" => "vermelho");
print_r(array_keys($array));

$array = array("azul", "vermelho", "verde", "azul", "azul");
print_r(array_keys($array, "azul"));

$array = array("cor"     => array("azul", "vermelho", "verde"),
               "tamanho" => array("pequeno", "medio", "grande"));
print_r(array_keys($array));

Example 2: php variables as keys in arrays

$id = 1;
$age = 2;    
$sort = "id"; // or "age";
    $Key = $$sort;
$arr = array($Key => 'string');

print_r($arr);