foreach() result as a $varaible

[Dolby]

Here is a simple script I made to help me understand how foreach works. How can I store the output of the foreach to a $varaible (not an array). All the examples of foreach i see only show how to store it into mysql in a bad way or echo it out.
Thanks for your help.

<FORM METHOD="POST" ACTION="<? echo $PHP_SELF?>">
<select name="resolutionarray[]" size="13" multiple="multiple" tabindex="6">
 <option value="All" selected="selected">All</option>
 <option value="640x480 ">640x480</option>
 <option value="800x600 ">800x600</option>
 <option value="1024x768 ">1024x768</option>
 <option value="1152x864 ">1152x864</option>
 <option value="1280x720 ">1280x720</option>
 <option value="1280x768 ">1280x768</option>
 <option value="1280x960 ">1280x960</option>
 <option value="1280x1024 ">1280x1024</option>
 <option value="1360x768 ">1360x768</option>
 <option value="1600x900 ">1600x900</option>
 <option value="1600x1024 ">1600x1024</option>
 <option value="1600x1200 ">1600x1200</option>
 </select>
<INPUT TYPE="submit" NAME="submit" VALUE="Submit">
</form>
<?
$resolutionarray = $HTTP_POST_VARS['resolutionarray'] ; 
foreach($resolutionarray as $resolution) {
echo "$resolution "; }
?>

[Gaheris]

$str = '';
foreach($resolutionarray as $resolution) {
    $str .=  $resolution; 
} 

[Dolby]

Wow that was fast. Thank you Gaheris!

[update] works perfect! thanks again