## sCard, sSize ##### *Description* Returns the cardinality of the set identified by key. 返回SET容器的成员数 ##### *Parameters* *key* ##### *Return value* *LONG* the cardinality of the set identified by key, 0 if the set doesn't exist. ##### *Example* ``` <pre class="calibre9">$redis->sAdd('key1' , 'member1'); $redis->sAdd('key1' , 'member2'); $redis->sAdd('key1' , 'member3'); /* 'key1' => {'member1', 'member2', 'member3'}*/ $redis->sCard('key1'); /* 3 */ $redis->sCard('keyX'); /* 0 */ ```