php aray_keys code example
Example: 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));