Redis系列-存储篇set主要操作函数小结
最近，总是以“太忙“为借口，很久没有blog了，凡事贵在恒，希望我能够坚持不懈，毕竟在blog的时候，也能提升自己。废话不说了，直奔主题”set“
redis set 是string类型对象的无序集合，set不管存储多少对象，对存储对象的add，remove和test操作的时间复杂度是O(1)。set最多能包含 232 - 1 个member。
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1、增加
语法：sadd key member[member...]
解释：对特定key的set增加一个或多个值，返回是增加元素的个数。注意：对同一个member多次add，set中只会保留一份。 www.2cto.com
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[root@xsf001 ~]# redis-cli
redis 127.0.0.1:6379> sadd stu zhangsan lisi wangwu #新增
(integer) 3
redis 127.0.0.1:6379> smembers stu #得到set的所有member
1) "wangwu"
2) "lisi"
3) "zhangsan"
redis 127.0.0.1:6379> sadd stu zhangsan #增加存在的member
(integer) 0
redis 127.0.0.1:6379> smembers stu
1) "wangwu"
2) "lisi"
3) "zhangsan"
redis 127.0.0.1:6379> sadd tech wangwu liming joe
(integer) 3
redis 127.0.0.1:6379> sadd tech jim
(integer) 1
redis 127.0.0.1:6379> smembers tech
1) "jim"
2) "liming"
3) "wangwu"
4) "joe"
2、查询
a）smembers
语法：smembers key
解释：获取set中的所有member
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redis 127.0.0.1:6379> smembers stu
1) "wangwu"
2) "lisi"
3) "zhangsan"
redis 127.0.0.1:6379> smembers tech
1) "jim"
2) "liming"
3) "wangwu"
4) "joe"
b）sismember
语法：sismember key member
解释：判断值是否是set的member。如果值是set的member返回1，否则，返回0
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redis 127.0.0.1:6379> sismember tech jim #jim 是set的member
(integer) 1
redis 127.0.0.1:6379> sismember tech jim001 #jim001 不是set的member
(integer) 0
c）scard
语法：scard key
解释：返回set的member个数，如果set不存在，返回0
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redis 127.0.0.1:6379>
scard tech # tech 存在
(integer) 4
redis 127.0.0.1:6379> scard stud #stud 不存在
(integer) 0
redis 127.0.0.1:6379> scard stu
(integer) 4
d）srandmember
语法：srandmember key
解释：从set中返回一个随机member
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redis 127.0.0.1:6379> srandmember stu
"zhangsan"
redis 127.0.0.1:6379> srandmember stu
"zhangsan"
redis 127.0.0.1:6379> srandmember stu
"wangwu"
redis 127.0.0.1:6379> srandmember stu
"zhangsan01"
3、删除
a）spop
语法：spop key
解释：移除并返回一个随机member
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redis 127.0.0.1:6379> smembers stu #pop前
1) "zhangsan01"
2) "wangwu"
3) "lisi"
4) "zhangsan"
redis 127.0.0.1:6379> spop stu #移除一个随机member
"lisi"
redis 127.0.0.1:6379> smembers stu #pop后
1) "zhangsan01"
2) "wangwu"
3) "zhangsan"
b）srem
语法：srem key member [member ...]
解释：移除一个或多个member
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redis 127.0.0.1:6379> smembers tech
1) "jim"
2) "liming"
3) "wangwu"
4) "joe"
redis 127.0.0.1:6379> srem tech jim #移除jim
(integer) 1
redis 127.0.0.1:6379> smembers tech
1) "liming"
2) "wangwu"
3) "joe"
redis 127.0.0.1:6379> srem tech liming joe #移除多个member
(integer) 2
redis 127.0.0.1:6379> smembers tech
1) "wangwu"
c）smove
语法：smove source destination member
解释：将source中的member移动到destination
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redis 127.0.0.1:6379> smembers tech #smove前
1) "wangwu"
redis 127.0.0.1:6379> smembers stu
1) "zhangsan01"
2) "wangwu"
3) "zhangsan"
redis 127.0.0.1:6379> smove stu tech zhangsan #将zhangsan 从stu移动到tech
(integer) 1
redis 127.0.0.1:6379> smembers stu #