Strange behavior with isset() returning true for an Array Key that does NOT exist

Question

I have the following array called $fruits:

Array
(
    [response] => Array
        (
            [errormessage] => banana
        )  

            


        

Answer 1

[n] is also a way to access characters in a string:

$fruits['response']['errormessage']['orange']
==
$fruits['response']['errormessage'][0] // cast to int
==
b (the first character, at position 0) of 'banana'

Use array_key_exists, possibly in combination with is_array.