Find Value Of Key In Associative Array

function find_by_key($searched, $array){
 if(!is_array($array)) return FALSE; // We haven't passed a valid array
 
 foreach($array as $key=>$value){
  if($key==$searched) return $value; // Match found, return value
 }
 return FALSE; // Nothing was found
}

$sample_array = array(
 'bmw'=>'fast',
 'mercedes'=>'luxury',
 'audi'=>'expensive'
);
 
echo find_by_key('audi', $sample_array);