为什么$ _SESSION和$ _COOKIE表现不一样？

Question

I've done some testing with $_SESSION and $_COOKIE because I they weren't working as I expected. I'd like to know why these lines of code behave differently.

$_SESSION[1] = 'foo';          // Does not work because of the integer
$_COOKIE[1] = 'bar';           // Works

$_SESSION['foo bar'] = 'foo';   // Works with the space
$_COOKIE['foo bar'] = 'bar';    // Does not work

I would have thought $_SESSION and $_COOKIE would be identical, other than being server side vs. client side. Are there any other differences between the two?

Answer 1

The answers on this question address some of the issues involved, but the short answer is that there are different restrictions depending on whether it's a session or a cookie. Sessions are restricted space-wise by different php.ini settings, cookies don't allow spaces in keys, etc.