[PHP] key length in an array

[Matthew Hanna]

Hey!
I was wondering if anyone knows if there is a limit to how long a string
can be when used as a key in an array.  Also, what if they are the same
up to some point?  For example,
$string = "SomeStringUsedAsKey";
$string2 = "SomeStringUsedAsKeyAgain";
$myArray[$string] = "some value";
$myArray[$string2] = "some other value";
Any thoughts on the matter?

Thanks!
Matthew Hanna