[K a M a L]

yes , I tried it with space and without and the problem is the same
but I made a solution

PHP Code:

$groups= 1,2,3,4,5,6; // without quotes
print_membergroup_row("Title", "recusergroup",2,array('usergroupid' => 0, 'membergroupids' => "'0,".$groups.",0'")); 


I added 0 at start and zero at end so it ignores the starting zero and end zero
but I'm still intersted to know why this happens