用户随机分组

gistfile1.php

//将用户进行随机分组，每组6个
$all = array(
    'x1','x2','x3','x4',
    'x5','x6','x7','x8',

);
define('GROUP_MAX', 6); 
$groupCount = getGroupCount(count($all));
$groups     = initGroups($groupCount);
shuffle($all);
while(! empty($all)) {
    $user    = getRandUser(& $all);
    $groupId = getRandGroupId($groupCount, $groups);
    if ($groupId === false) {
        die ('oh, what happen');
    }   
    $groups[$groupId][] = $user;
}
var_dump($groups);
// 获取分组数量

function getGroupCount($count)
{
    if ($count % GROUP_MAX == 0) {
        return $count / GROUP_MAX;
    }   
    return intval($count / GROUP_MAX) + 1;
}
// 随机获取一个用户
function getRandUser(& $users)
{
    $randKey = array_rand($users);
    $rand    = $users[$randKey];
    unset($users[$randKey]);
    return $rand;
}
// 初始化分组
function initGroups($count)
{
    $groups = array_fill(1, $count, array());
    return $groups;
}
// 随机取出一个不满的组
function getRandGroupId($groupCount, $groups)
{
    $groupIds = range(1, $groupCount);
    shuffle($groupIds);
    foreach ($groupIds as $groupId) {
        if (count($groups[$groupId]) < GROUP_MAX) {
            return $groupId;
        }
    }
    return false;
}