multi-dimension arrays in PHP

[Robert Edwards]

Not really a Linux question, per say, but it is running on a Linux-based 
server :-)

I have a multi-dimensioned array that I am saving in the super-global session 
variable, $_SESSION, thus:

$myarray[$x][$y][$z] = "some string";
$_SESSION['myarray'] = $myarray;

>From the documentation on arrays in the online PHP manual it states that 
assigning arrays like this will involve value copying:

"You should be aware, that array assignment always involves value copying. You 
need to use the reference operator to copy an array by reference."

I add other values to $myarray, but I don't expect these to be saved in the 
session.

When the next page loads, I do this:

$myarray = $_SESSION['myarray'];

and now $myarray does contain the extra added values, which implies that they 
were also saved into the session store. What I really want is to only see the 
original stuff that was saved in $myarray before I saved it in the session.

Anyone know why this might be happening, how to avoid it, or where I should 
ask for more help?

Cheers,

Bob Edwards.