是一种无序集合,不能有重复元素,添加元素不讲头尾,是无序的
SADD key member [member...] 和列表一样,key代表集合名,如果key不存在则创建一个集合,值可以有一个或多个
SADD key member [member...]
会返回一个1或0表示成功和失败,如果添加重复的元素则会返回0
1
0
SISMEMBER key member判断元素是否在一个集合中
SISMEMBER key member
SREM key member [member...]删除一个或多个元素
SREM key member [member...]