php遍历memcache全部键值

?????? $items=$this->memcache->getExtendedStats ('items');???????
??? ??? $items=$items["127.0.0.1:11211"]['items'];
??? ??? foreach($items as $key=>$values)
??? ??? {???
??? ??? ??? $number=$key;??? ???
??? ??? ??? $str=$this->memcache->getExtendedStats ("cachedump",$number,0);??? ???
??? ??? ??? $line=$str["127.0.0.1:11211"];??????????? ??? ???
??? ??? ??? if( is_array($line) && count($line)>0)
??????????? {??? ??? ??? ??? ???
???? ??? ??? ??? foreach($line as $key=>$value)
??? ??? ??? ??? {??????????????????
???????????????????? $array[$key] = $value[1];?????????????????
??? ??? ??? ??? }
??????????? }
?????? }
上面取到的是其键和该键的生成时间，键的过期时间好像取不到，找了很多地方，都没有说到该如何取键。