How to set programmatically multiple arguments for views contextual filters
First you should set this option:
View → Advanced → Your Contextual Filter → More → Allow Multiple Values. 
Then when passing array should be with '+', so, your example:

$array = array('3250+32');
$view = views_get_view('myview');
$view-&gt;set_display("myblock");
$view-&gt;set_arguments($array);
$view-&gt;pre_execute();
$view-&gt;execute();
$content = $view-&gt;render();