What's quicker and better to determine if an array key exists in PHP?

Question

Consider these 2 examples...

$key = 'jim';  // example 1 if (isset($array[$key])) {     // ... }  // example 2     if (array_key_exists($key, $array)) {     // ... } 

I'm interested in knowing if either of these are better. I've always used the first, but have seen a lot of people use the second example on this site.

So, which is better? Faster? Clearer intent?

Answer 1

isset() is faster, but it's not the same as array_key_exists().

array_key_exists() purely checks if the key exists, even if the value is NULL.

Whereas isset() will return false if the key exist and value is NULL.