I can't assign anything to an array in php through foreach, any idea?

See more:

PHP

I want to create three table in a row in my page & put these values in, I try to remove each value after echoing them but i cant remove the value of $Column[$key] i used three way but they don't work. now my question is why? and how can i do that?
Is there any better way?

<?php
$i = 0;
while(count($TBClm)>0)
{?>
    <div class="col-25p">
        <table>
            <tbody>
            <?php
            $j = 0;
            foreach ($TBClm as $Ctg => $Column)
            {
                ++$j;
                ?>
                <tr class="category">
                    <td>-<?php echo $Ctg;?>-</td>
                </tr>
                <?php
                foreach ($Column as $key => $values)
                {
                    if($Column[$key]==null)
                       continue;

                    ++$j;
                    ?>
                    <tr>
<td>
<?echo $values[0];?>
<td>
</tr>
                <?php

                    $Column[$key]=null;//actually i want to remove this part
//I used unset() and array_shift() but they didn't work 

                    if ($j > 10)
                        break;
                }
                if ($j > 10)
                    break;

                unset($TBClm[$Ctg]);
            }?>
            </tbody>
        </table>
    </div>
<?php
}?>