PHP除以零警告并带有检查

Question

I have a script that does some math and makes an excel sheet but i randomly get a

Warning: Division by zero in myfile.php on line 170

Which throws off my header() changes.. I say that its random because it will work one time but if i refresh the page it breaks the most confusing part is that i also have a check if its zero here is the code

      167    if($cartonCount > 0){
      168     echo  "-----" . $cartonCount . "-----";
      169    $mellow = $qty/$cartonCount;
      170    $leftovers = $qty % $cartonCount;
      171    for($x = 1 ; $x <= $mellow ; $x++){

If the carton count is 0 it shouldn't run at all yet i still get the warning.. if anyone has an idea let me know here is a sample of the out put

-2.38----------7.63----------12----------10----------7.5---------       
7.5----------4.5----------4.5----------4.5----------4.5----------7.5- 
---------1----------9.5----------7.5----------2.38----------0.06-----

Warning: Division by zero in /nfs/c08/h02/mnt/122022/domains/superstructs.com/html/catalog/test/samples/upsExport.php on line 170

-----2.38----------7.63----------7.5----------7.5----------2.38------
----0.06-----

Answer 1

Then, I'm putting this in as answer:

It might be because the value is NULL which, in fact, is not >0. But it will still give you that error

Answer 2

I notice that the place where it breaks is when $cartonCount is "0.06". I suspect that $cartonCount is being stored as a string, possibly with the European style 0,06 decimal notation. When PHP tries to convert that to a number, it sees it as a zero. I'm not sure why it is acting differently for the modulo operator and not for division or equality checks, but putting $cartonCount = intval($cartonCount) before line 167 should make things act consistently (although it might end up interpreting your 0.06 as a zero).

Answer 3

The modulo operator converts (or rounds) the second number to an integer. 0.06 results in 0 which creates the warning.

Possible options are for example casting to integer or round() before checking > 0, round up using ceil() or check > 1.

Based on the context ceil() seems to be the best option.