Check if a key exists and get a corresponding value from an array in PHP

if (array_key_exists($key_to_check, $things)) {
    return $things[$key_to_check];
}

I know this question is very old but for those who will come here It might be useful to know that in php7 you can use Null Coalesce Operator

if ($value = $things[ $key_to_check ] ?? null) {
      //Your code here
}

if(isset($things[$key_to_check])){
    echo $things[$key_to_check];
}