array_key_exists but with an object as the key

Question

What's the best way to check if an object exists as the key of an array?

// key: $obj, array: $array
array_key_exists($obj, $array);

Results in a PHP Warning: "1st param should be string or integer".

Answer 1

I'm pretty sure you're wanting property_exists()

edit: at time of answer, the title was "array_key_exists but with objects"