foreach() invalid argument

Question

I use this PHP function to delete some array elements.

function deleteEx ($ind, $kl) {
     global $exs;

     foreach ( $exs as $key => $examples )
             if ( $examples['KL'] == $kl && $examples['id'] == $ind)
                unset( $exs[$key] );
}

and I have 2 different functions that calls it during the computation: 1st one is this:

function deleteSub ($editing) {
     global $subs, $exs;

     $kl= $_POST['kl'];

     foreach ( $subs as $key => $subject )
             if ( $subject['knowledgeLevel'] == $kl )
                unset( $subs[$key] );

     if ($editing == 0) {
          for ( $i=1; $i <= count($exs); $i++)
              deleteEx($i, $kl);

          header("refresh:0;url=backdoor.php");
          exit;
     }
}

2nd one is this:

function editSub () {
     $kl= $_POST['kl'];

     for ($i= 1; $i<= $_POST['nofexamples']; $i++) {
         if (strcmp ($_POST['oldex'.$i], $_POST['example'.$i]) != 0)
            deleteEx($i, $kl);
     }
     deleteSub (1);
}

Calling the function deleteEx within the first function everything works just fine and the result is the expected one. Calling the funcion deleteEx within the second function I get the warning: Invalid argument supplied for foreach() and the results are not what I expected. Any idea of how eliminate the warning? (I guess that's the reason why the function doesn't work fine).

Answer 1

First of all there's a syntax error on your globals

Replace

global $subs $exs;

with

global $subs,$exs;