PHP会话在多维时不会持久化

I'm having a little issue, when I do this:

$_SESSION['cartItems'] = array();

It works fine, and it creates a cartItems array in the session.

But when I do this:

$_SESSION[2]['cartItems'] = array();

This works until I refresh the page, then it forgets this session array?

I tried to create the 2 array first:

$_SESSION[2] = array();
$_SESSION[2]['cartItems'] = array();

But still does not work like it is supposed to do.

How can I solve this?

Numeric keys are converted to strings because the $_SESSION variable is an associative array. You might want to try using $_SESSION["2"] when assigning or retrieving values.

Further more, it looks to me like you are trying to persist several cart arrays, so why not use something like this instead:

$_SESSION['carts'] = array();
$_SESSION['carts'][0] = array();
$_SESSION['carts'][1] = array();
...

Or even $_SESSION['carts'][0]['cartItems'] = array()

Some related posts for further reading:

• Why can't I use intergers as an index in a PHP $_SESSION array?
• A numeric string as array key in PHP

I suggest you to use as serialized object.

$_SESSION['carts'] = serialize(array(0=> "foo", 1=> array("bar")));

In this case you can store complex data and it will be secure & clean.