Divide php for cycle in 2 columns

I have a code:

<?php for ($i = 0; $i < sizeof($categories); $i = $i + 4) { ?>
<?php for ($j = $i; $j < ($i + 4); $j++) { ?>
<?php if (isset($categories[$j])) { ?>
  <a href="<?php echo $categories[$j]['href']; ?>"><img src="<?php echo $categories[$j]['thumb']; ?>" title="<?php echo $categories[$j]['name']; ?>" alt="<?php echo $categories[$j]['name']; ?>" style="margin-bottom: 3px;" /></a><br />
  <a开发者_如何学Python href="<?php echo $categories[$j]['href']; ?>"><?php echo $categories[$j]['name']; ?></a>
  <?php } ?>
<?php } ?>
<?php } ?>

I want to place these categories in 2-column like this:

<div class="span-8">
 <div class="product">
 product1
 </div>
</div>
<div class="span-8 last">
 <div class="product">
 product2
 </div>
</div>

How can I do this?

<?php 
for ($i = 0; $i < sizeof($categories); $i = $i + 4) { 
for ($j = $i; $j < ($i + 4); $j++) { 
if (isset($categories[$j])) { 
if($colcount % 2){
$col1+="<div class='product'><a href='".$categories[$j]['href']."'><img src='".$categories[$j]['thumb']."' title='".$categories[$j]['name']."' alt='".$categories[$j]['name']."' style='margin-bottom: 3px;' /></a></div><a href='".$categories[$j]['href']."'>".$categories[$j]['name']."</a>";
}else{
$col2+="<div class='product'><a href='".$categories[$j]['href']."'><img src='".$categories[$j]['thumb']."' title='".$categories[$j]['name']."' alt='".$categories[$j]['name']."' style='margin-bottom: 3px;' /></a></div><a href='".$categories[$j]['href']."'>".$categories[$j]['name']."</a>";
}
$colcount++;
}
}
}
echo "<div class='span-8'>".$col1."</div><div class='span-8 last'>".$col2."</div>";

Or you could do it the easy way and make it a fluid <ul> that way they would do it automatically

I don't really see the correlation between the php and the html code, but I think you just need to output a different css class for each odd category:

$last = false;
foreach($categories as $c) {
  //Output category html
  ?>
    <div class="span <?=($last)?'last':''?>">.....</div>
  <?

  $last != $last;

}