Redis 的数据类型 - Set 集合类型：无序集合
SADD：向集合中添加元素
语法：SADD key member [...]
SADD web www.baidu.com
SADD web www.sina.com.cn www.amazon.com
SADD web www.taobao.com www.bilibili.com
127.0.0.1:6379> SADD web www.baidu.com (integer) 1 127.0.0.1:6379> SADD web www.sina.com.cn www.amazon.com (integer) 2 127.0.0.1:6379> SADD web www.taobao.com www.bilibili.com (integer) 2 127.0.0.1:6379> SMEMBERS web 1) "www.amazon.com" 2) "www.sina.com.cn" 3) "www.baidu.com" 4) "www.taobao.com" 5) "www.bilibili.com"
SMEMBERS：返回指定集合中的元素
语法：SMEMBERS key
SMEMBERS web
SISMEMBER：检测 member 是否是集合中的成员
语法：SISMEMBER key member
SISMEMBER web www.baidu.com
SISMEMBER web www.google.com #不存在返回 0 #
127.0.0.1:6379> SISMEMBER web www.baidu.com (integer) 1 127.0.0.1:6379> SISMEMBER web www.google.com (integer) 0
SREM：删除集合中的一个或者多个成员
语法：SREM key member [member...]
SREM web www.baidu.com
SREM web www.taobao.com www.bilibili.com #当同时删除多个 member，有不存在的或删除失败的 member 时，返回值时删除成功的个数#
127.0.0.1:6379> SMEMBERS web 1) "www.baidu.com" 2) "www.taobao.com" 3) "www.sina.com.cn" 4) "www.bilibili.com" 5) "www.amazon.com" 127.0.0.1:6379> SREM web www.taobao.com www.baidu.com (integer) 2 127.0.0.1:6379> SREM web www.taobao.com www.bilibili.com (integer) 1
SPOP：删除并返回集合中的一个随机元素
语法：SPOP key
SADD course php java ios android c c++ js
SPOP course
SMEMBERS course
127.0.0.1:6379> SADD course php java ios android c c++ js (integer) 7 127.0.0.1:6379> SPOP course "php" 127.0.0.1:6379> SMEMBERS course 1) "c" 2) "ios" 3) "android" 4) "c++" 5) "java" 6) "js"
SRANDMEMBER：随机返回集合中的元素
语法：SRANDMEMBER key count
# count 如果小于集合中的元素，返回 count 个随机元素的集合数组；如果 count 大于集合中元素的个数，这时候会返回整个集合，如果 count 为负数，返回数组的长度是 count 的绝对值，数组中的成员可能出现重复#
SRANDMEMBER course
SRANDMEMBER course 2
SRANDMEMBER course 50
SRANDMEMBER course -2
127.0.0.1:6379> SRANDMEMBER course "ios" 127.0.0.1:6379> SRANDMEMBER course 2 1) "c" 2) "java" 127.0.0.1:6379> SRANDMEMBER course 50 1) "ios" 2) "c++" 3) "android" 4) "c" 5) "js" 6) "java" 127.0.0.1:6379> SRANDMEMBER course -2 1) "ios" 2) "js"
SDIFF：返回集合间的差集
语法：SDIFF key key ...
SADD testSet1 a b c d e
SADD testSet2 b c d e f
SDIFF testSet1 testSet2 #在集合 1 中，不在集合 2 中的元素#
SDIFF testSet2 testSet1 #在集合 2 中，不在集合 1 中的元素#
SADD testSet3 x y z
SDIFF testSet1 testSet2 testSet3 #在两个以上的集合中取差集的时候，先对前两个进行取值，所得到的结果再与后面的集合进行对比，当差集为空的时候回报错#
127.0.0.1:6379> SADD testSet1 a b c d e (integer) 5 127.0.0.1:6379> SADD testSet2 b c d e f (integer) 5 127.0.0.1:6379> SDIFF testSet1 testSet2 1) "a" 127.0.0.1:6379> SDIFF testSet2 testSet1 1) "f" 127.0.0.1:6379> SADD testSet3 x y z (integer) 4 127.0.0.1:6379> SDIFF testSet1 testSet2 testSet3 1) "a" 127.0.0.1:6379> SADD testSet3 x y z a (integer) 4 127.0.0.1:6379> SDIFF testSet1 testSet2 testSet3 (empty list or set)
SINTER：返回集合间的交集
语法：SINTER key key...
SINTER testSet1 testSet2
SINTER testSet1 testSet2 testSet3
SADD testSet3 b
127.0.0.1:6379> SINTER testSet1 testSet2 1) "c" 2) "b" 3) "d" 4) "e" 127.0.0.1:6379> SINTER testSet1 testSet2 testSet3 (empty list or set) 127.0.0.1:6379> SADD testSet3 b (integer) 1 127.0.0.1:6379> SINTER testSet1 testSet2 testSet3 1) "b"
SUNION：返回集合中并集
语法：SUNION key key...
SUNION testSet1 testSet2
SUNION testSet1 testSet2 testSet3
127.0.0.1:6379> SUNION testSet1 testSet2 1) "a" 2) "c" 3) "f" 4) "b" 5) "d" 6) "e" 127.0.0.1:6379> SUNION testSet1 testSet2 testSet3 1) "a" 2) "c" 3) "x" 4) "f" 5) "b" 6) "d" 7) "z" 8) "e" 9) "y"
SCARD：返回集合中元素个数
语法：SCARD key
SCARD testSet1
127.0.0.1:6379> SCARD testSet1 (integer) 5
SDIFFSTORE：将差集结果保存到指定集合中
语法：SDIFFSTORE destination key key ...
SDIFFSTORE diffSet testSet1 testSet2
SMEMBERS diffSet #返回值为集合 1 和 2 的差集 a #
SADD diffSet b #再添加一个元素到 diffSet 里，这是 diffSet 里有两个元素了#
SMEMBERS diffSet
SDIFFSTORE diffSet testSet2 testSet1
SMEMBERS diffSet #原本 diffSet 里原有的值被清空了，重新写入新值 f #
127.0.0.1:6379> SDIFFSTORE diffSet testSet1 testSet2 (integer) 1 127.0.0.1:6379> SMEMBERS diffSet 1) "a" 127.0.0.1:6379> SADD diffSet b (integer) 1 127.0.0.1:6379> SMEMBERS diffSet 1) "a" 2) "b" 127.0.0.1:6379> SDIFFSTORE diffSet testSet2 testSet1 (integer) 1 127.0.0.1:6379> SMEMBERS diffSet 1) "f"
SINTERSTORE：将交集的结果保存在指定集合中
语法：SINTERSTORE destination key key ...
SUNIONSTORE：将并集的结果保存到指定集合中
语法：SUNIONSTORE destination key key ...
SMOVE：将集合中元素移动另外一个集合中
语法：SMOVE source destination member #原子操作#
SMOVE testSet2 testSet1 f
SADD testSet2 f
SMOVE testSet2 testSet1 f
SMEMBERS testSet2
127.0.0.1:6379> SMEMBERS testSet1 1) "a" 127.0.0.1:6379> SMEMBERS testSet2 1) "c" 2) "f" 3) "b" 4) "d" 5) "e" 127.0.0.1:6379> SMOVE testSet2 testSet1 f (integer) 1 127.0.0.1:6379> SMEMBERS testSet2 1) "c" 2) "b" 3) "d" 4) "e" 127.0.0.1:6379> SMEMBERS testSet1 1) "a" 2) "f"
