$arr=array(
5=>‘奖项一‘,
10=>‘奖项二‘,
60=>‘奖项三‘,
25=>‘奖项四‘);
$pool=array();
foreach($arr as $k=>$v){
echo count($pool).‘<br>‘;
$pool+=array_fill(count($pool),$k,$v);
}
echo ‘<pre>‘;
print_r($pool);
echo $pool[rand(0,99)];
原文：http://www.cnblogs.com/darktime/p/3818499.html