private function rand_words()
{
$letter_list = 'abcdefghijklmnopqrstuvwxyz';
$len = strlen($letter_list);
$return_list = array();
$max_kw_length = 40;
//获取最多多少关键词
$max_dis_length = 32;
$filter_array = $this->getFilterArray();
$cache_rand_words = \common\models\DiseaseSymptomMerge::getCacheRandWords($max_kw_length, $filter_array);
for ($i = 0; $i < $len; $i++) {
$wd = strtoupper($letter_list[$i]);
$ret = isset($cache_rand_words[$wd]) ? $cache_rand_words[$wd] : array();
if (count($ret) > 0) {
$rand_num = count($ret) > $max_dis_length ? $max_dis_length : count($ret);
$rand_keys = array_rand($ret, $rand_num);
if (is_array($rand_keys)) {
foreach ($rand_keys as $k) {
$return_list[$wd][] = $ret[$k];
}
} else {
$return_list[$wd][] = $ret[0];
}
} else {
$return_list[$wd] = array();
}
}
return $return_list;
}
