Bug in unsetting?

[sfullman]

Hello,
I'm actually a fairly experienced programmer with PHP but I do have one problem. When the shopping cart has been submitted and the funds captured, I "empty the cart" like this:

unset($HTTP_SESSION_VARS['shopCart']);

So far so good right? Now if I go "back" to the first page, which iterates through the cart and gets a total, I get this message:

Warning: Invalid argument supplied for foreach() in /home.... etc.

Yet I'm "guarding" the foreach() by making sure it's got an element first, why am I getting this warning?

Here is the code that produces the error:

if(sizeof($HTTP_SESSION_VARS['shopCart'])>0){
	/* the size is showing as 1, i.e. one item */
	foreach($HTTP_SESSION_VARS['shopCart'] as $q=>$r){ //this is the line that produces the warning -- I have no idea why.
		if($HTTP_SESSION_VARS['Login']=='guest'){
			$multiplier=$r['WholesalePrice'];
		}else{
			$multiplier=$r['RetailPrice'];
		}
		if($r[1]>0){$currentOrder += $r[1] * $multiplier;}
}}

Any suggestions? Thank you, Sam Fullman

[theslinky]

try using isset to check whether that variable is set.

also, unless you're using an old version of PHP, i suggest you use $_SESSION[] instead of $HTTP_SESSION_VARS[].

-sridhar

[the_Igel]

the problem may be in the fact that count() (or sizeof()) returns 1 when the variable isn't actually an array. Then you have problems applying foreach to a scalar variable.

[devarticles]

when you empty the variable, you no longer have the array, therefore the error, try using this code instead

if(sizeof($HTTP_SESSION_VARS['shopCart'])>0){ 
/* the size is showing as 1, i.e. one item */ 
if(if_array($HTTP_SESSION_VARS['shopCart'])) {
foreach($HTTP_SESSION_VARS['shopCart'] as $q=>$r){ //this is the line that produces the warning -- I have no idea why. 
if($HTTP_SESSION_VARS['Login']=='guest'){ 
$multiplier=$r['WholesalePrice']; 
}else{ 
$multiplier=$r['RetailPrice']; 
} 
if($r[1]>0){$currentOrder += $r[1] * $multiplier;} 
}}} 

this will just stop the error