تابع ()array_key_exists در PHP

<?php
$a=array("Volvo"=>"XC90","BMW"=>"X5");
if (array_key_exists("Volvo",$a))
  {
  echo "Key exists!";
  }
else
  {
  echo "Key does not exist!";
  }
?>
<?php
$a=array("Volvo"=>"XC90","BMW"=>"X5");
if (array_key_exists("Volvo",$a))
  {
  echo "Key exists!";
  }
else
  {
  echo "Key does not exist!";
  }
?>اجرای کد

array_key_exists(key, array)