iterating in two arrays in the same for loop

I'm learning php, I want to iterate in two arrays in the same for loop, how ? this is the code I have, line 8 to line 14 for example, but it gives an array instead of an element, what to do? please be easy with on me I'm still new to this field.

<tr>
<td><?php echo $val->title ?></td>
<td><?php echo $val->content?></td>
<td><?php echo $val->owner ?></td>
<?php } ?>

<?php
foreach ($users as $val) {
?>
<td><?php echo str_replace("-", "%", $val->email) ?></td>
<?php }?>
<?php foreach ($maincat as $val) {?>
<td><?php echo str_replace("-","%",$val->maincat_name) ?></td>
<?php }?>

<?php foreach ($category as $val) {?>
<td><?php echo str_replace("-","%",$val->category_name) ?></td>
<?php }?>

<?php foreach ($sub_category as $val) {?>
<td><?php echo str_replace("-","%",$val->sub_category_name) ?></td>
<?php }?>

<?php foreach ($sub_sub_category as $val) {?>
<td><?php echo str_replace("-","%",$val->sub_sub_category_name) ?></td>
<?php }?>

</tr>

can somebody help ?