（三）Redis——Set
SADD key value
SMEMBERS
127.0.0.1:6379> SADD set aaa
1
127.0.0.1:6379> SMEMBERS set
aaa
127.0.0.1:6379> SADD set aaa
0
127.0.0.1:6379> SMEMBERS set
aaa
SISMEMBER
判断 aaa 是否在 set 中
127.0.0.1:6379> SISMEMBER set aaa
1
127.0.0.1:6379> SISMEMBER set bbb
0
127.0.0.1:6379> SREM set aaa
1
127.0.0.1:6379> SMEMBERS set
集合的操作
127.0.0.1:6379> SINTER SUNION SDIFF