Redis的数据类型 - set、sorted_set

set

保存多个字符串元素，但不允许有重复的元素，并且集合set是无序的，不能通过索引下标获取元素

set除了基本的增删改查，还支持多个集合的取交集、并集、差集等操作，下面来看一下命令help @set

sadd

SADD key member [member ...]
summary: Add one or more members to a set
since: 1.0.0

添加元素

127.0.0.1:6379[1]> del k1 
(integer) 1
127.0.0.1:6379[1]> sadd k1 a b c
(integer) 3
127.0.0.1:6379[1]> sadd k1 b c
(integer) 0

smembers

SMEMBERS key
summary: Get all the members in a set
since: 1.0.0

获取所有元素，并且结果是无序的

127.0.0.1:6379[1]> smembers k1
1) "a"
2) "c"
3) "b"

srem

SREM key member [member ...]
summary: Remove one or more members from a set
since: 1.0.0

删除元素

127.0.0.1:6379[1]> srem k1 b
(integer) 1
127.0.0.1:6379[1]> srem k1 cccc
(integer) 0
127.0.0.1:6379[1]> smembers k1
1) "a"
2) "c"

scard

SCARD key
summary: Get the number of members in a set
since: 1.0.0

计算元素个数，scard的时间复杂度O(1)，它不会遍历集合所有的元素，而是直接用Redis内存提供的变量

127.0.0.1:6379[1]> scard k1
(integer) 2

sismember

SISMEMBER key member
summary: Determine if a given value is a member of a set
since: 1.0.0

判断元素是否在集合中，有返回1，无返回0

127.0.0.1:6379[1]> sismember k1 a
(integer) 1
127.0.0.1:6379[1]> sismember k1 aaa
(integer) 0

srandmember

SRANDMEMBER key [count]
summary: Get one or multiple random members from a set
since: 1.0.0

随机从集合返回指定个数元素，元素不会从集合中删除

count的取值：

• 正数：取出一个去重的结果集（不能超过已有集）

• 负数：取出一个带重复的结果集，一定返回满足你要的数量

• 如果：0，不返回

127.0.0.1:6379[1]> sadd k1 a b c d e
(integer) 3
127.0.0.1:6379[1]> srandmember k1 3
1) "c"
2) "a"
3) "d"
127.0.0.1:6379[1]> srandmember k1 -3
1) "d"
2) "a"
3) "d"

spop

SPOP key [count]
summary: Remove and return one or multiple random members from a set
since: 1.0.0

从集合中随机弹出元素，元素会从集合中删除

127.0.0.1:6379[1]> spop k1 
"a"
127.0.0.1:6379[1]> smembers k1
1) "e"
2) "c"
3) "b"
4) "d"

sinter、sinterstore

SINTER key [key ...]
summary: Intersect multiple sets
since: 1.0.0

SINTERSTORE destination key [key ...]
summary: Intersect multiple sets and store the resulting set in a key
since: 1.0.0

sinter求多个集合的交集，sinterstore将交集的结果保存

127.0.0.1:6379[1]> del k1 k2
(integer) 1
127.0.0.1:6379[1]> sadd k1 a b c d 
(integer) 4
127.0.0.1:6379[1]> sadd k2 c d e
(integer) 3
127.0.0.1:6379[1]> sinter k1 k2
1) "c"
2) "d"
127.0.0.1:6379[1]> sinterstore desinter k1 k2
(integer) 2
127.0.0.1:6379[1]> smembers desinter
1) "c"
2) "d"

sunion、sunionstore

SUNION key [key ...]
summary: Add multiple sets
since: 1.0.0

SUNIONSTORE destination key [key ...]
summary: Add multiple sets and store the resulting set in a key
since: 1.0.0

sunion求多个集合的并集，sunionstore将并集结果保存

127.0.0.1:6379[1]> sunion k1 k2
1) "d"
2) "e"
3) "c"
4) "a"
5) "b"
127.0.0.1:6379[1]> sunionstore desunion k1 k2
(integer) 5
127.0.0.1:6379[1]> smembers desunion
1) "d"
2) "e"
3) "c"
4) "a"
5) "b"

sdiff、sdiffstore

SDIFF key [key ...]
summary: Subtract multiple sets
since: 1.0.0

SDIFFSTORE destination key [key ...]
summary: Subtract multiple sets and store the resulting set in a key
since: 1.0.0

sdiff求多个集合的差集，sdiffstore将差集结果保存

127.0.0.1:6379[1]> sdiff k1 k2
1) "a"
2) "b"
127.0.0.1:6379[1]> sdiffstore desdiff k1 k2
(integer) 2
127.0.0.1:6379[1]> smembers desdiff
1) "a"
2) "b"

smove

SMOVE source destination member
summary: Move a member from one set to another
since: 1.0.0

将指定成员 member 元素从 source 集合移动到 destination 集合

127.0.0.1:6379[1]> smembers k1
1) "a"
2) "c"
3) "b"
4) "d"
127.0.0.1:6379[1]> smembers k2
1) "e"
2) "c"
3) "d"
127.0.0.1:6379[1]> smove k1 k2 a
(integer) 1
127.0.0.1:6379[1]> smembers k1
1) "c"
2) "b"
3) "d"
127.0.0.1:6379[1]> smembers k2
1) "e"
2) "a"
3) "c"
4) "d"

sscan

SSCAN key cursor [MATCH pattern] [COUNT count]
summary: Incrementally iterate Set elements
since: 2.8.0

用于迭代集合中键的元素。cursor - 游标，pattern - 匹配的模式，count - 指定从数据集里返回多少元素，默认值为 10 。

127.0.0.1:6379[1]> sadd k4 apple banana orange 
(integer) 3
127.0.0.1:6379[1]> sscan k4 0 match a*
1) "0"
2) 1) "apple"
127.0.0.1:6379[1]> sscan k4 1 match a*
1) "0"
2) (empty list or set)

内部编码

• intset（整数集合）：当集合中的元素都是整数且元素个数小于set-max-intset-entries配置（默认512个）时，Redis使用intset作为集合的内部实现，从而减少内存的使用。
• hashtable（哈希表）：当集合类型无法满足intset的条件时，Redis使用hashtable作为集合的内部实现

127.0.0.1:6379[1]> object encoding k1
"hashtable"
127.0.0.1:6379[1]> sadd intkey 1 2 3 4
(integer) 4
127.0.0.1:6379[1]> object encoding intkey
"intset"
127.0.0.1:6379[1]> sadd intkey 1 2 3 4 5 ... 512 513
(integer) 4
127.0.0.1:6379[1]> object encoding intkey
"hashtable"

应用

• 标签 sadd

给用户添加标签

sadd user:1:tags tag1 tag2 tag3
sadd user:2:tags tag1 tag4 tag5

给标签添加用户

sadd tag1:users user:1 user:2
sadd tag2:users user:2

删除用户下的标签

srem user:1:tags tag3

删除标签下的用户

srem tag1:users user2

计算用户共同感兴趣的标签

sinter user:1:tags user:2:tags

• 抽奖

  1. spop

     例如每个人只能中一个奖，中奖后不能在参与其他奖项，需要在集合中删除

  2. srandmember

     每个人可以重复中奖

sorted_set

有序集合保留集合不能重复的特性，又可以排序，为每一个元素设置一个分数（score）作为排序的依据。

list，set，sorted_set的异同点

数据结构	是否允许重复元素	是否有序	有序实现方式	应用场景
list	是	是	索引下标	时间轴、消息队列
set	否	否	无	标签、抽奖、社交等
sorted_set	否	是	分值	排行榜系统、社交等

下面看一下sorted_set的相关命令 help @sorted_set

zadd

ZADD key [NX|XX] [CH] [INCR] score member [score member ...]
summary: Add one or more members to a sorted set, or update its score if it already exists
since: 1.2.0

添加成员

• nx：member必须不存在，才可以设置成功，用于添加
• xx：member必须存在，才可以设置成功，用于更新
• ch：返回此次操作后，有序集合元素和分数发生变化的个数
• incr：对score做增加，相当于zincrby

sorted_set相比set提供了排序字段，但是也产生了代价，zadd的时间复杂度为O(long(n))，sadd的事件复杂度为O(1)。

127.0.0.1:6379[1]> zadd k1 100 demeter
(integer) 1

zcard

ZCARD key
summary: Get the number of members in a sorted set
since: 1.2.0

计算成员个数

127.0.0.1:6379[1]> zcard k1
(integer) 1
127.0.0.1:6379[1]> zadd k1 120 tom
(integer) 1
127.0.0.1:6379[1]> zcard k1
(integer) 2

zscore

ZSCORE key member
summary: Get the score associated with the given member in a sorted set
since: 1.2.0

计算某个成员的分数

127.0.0.1:6379[1]> zscore k1 tom
"120"

zrank

ZRANK key member
summary: Determine the index of a member in a sorted set
since: 2.0.0

计算成员的排名，zrank是从分数从低到高返回排名

127.0.0.1:6379[1]> zrank k1 tom
(integer) 1
127.0.0.1:6379[1]> zrank k1 demeter
(integer) 0

zrevrank

ZREVRANK key member
summary: Determine the index of a member in a sorted set, with scores ordered from high to low
since: 2.0.0

计算成员的排名，zrevrank是从分数从高到低返回排名

127.0.0.1:6379[1]> zrevrank k1 tom
(integer) 0
127.0.0.1:6379[1]> zrevrank k1 demeter
(integer) 1

zrem

ZREM key member [member ...]
summary: Remove one or more members from a sorted set
since: 1.2.0

删除成员

127.0.0.1:6379[1]> zrem k1 tom
(integer) 1

zincrby

ZINCRBY key increment member
summary: Increment the score of a member in a sorted set
since: 1.2.0

增加成员的分数

127.0.0.1:6379[1]> zincrby k1 40 demeter
"140"
127.0.0.1:6379[1]> zscore k1 demeter
"140"

zrange

ZRANGE key start stop [WITHSCORES]
summary: Return a range of members in a sorted set, by index
since: 1.2.0

返回指定排名范围的成员，zrange按照分值排序从低到高返回，加上withscores，同时会返回成员的分数

127.0.0.1:6379[1]> zadd k1 120 tom
(integer) 1
127.0.0.1:6379[1]> zadd k1 90 jack
(integer) 1
127.0.0.1:6379[1]> zadd k1 200 maek
(integer) 1
127.0.0.1:6379[1]> zadd k1 170 chery
(integer) 1

127.0.0.1:6379[1]> zrange k1 0 -1 withscores
 1) "jack"
 2) "90"
 3) "tom"
 4) "120"
 5) "demeter"
 6) "140"
 7) "chery"
 8) "170"
 9) "maek"
10) "200"
127.0.0.1:6379[1]> zrange k1 1 3 withscores
1) "tom"
2) "120"
3) "demeter"
4) "140"
5) "chery"
6) "170"

zrevrange

ZREVRANGE key start stop [WITHSCORES]
summary: Return a range of members in a sorted set, by index, with scores ordered from high to low
since: 1.2.0

返回指定排名范围的成员，zrange按照分值排序从高到低返回

127.0.0.1:6379[1]> zrevrange k1 0 -1 withscores
 1) "maek"
 2) "200"
 3) "chery"
 4) "170"
 5) "demeter"
 6) "140"
 7) "tom"
 8) "120"
 9) "jack"
10) "90"
127.0.0.1:6379[1]> zrevrange k1 1 3  withscores
1) "chery"
2) "170"
3) "demeter"
4) "140"
5) "tom"
6) "120"

zrangebyscore

ZRANGEBYSCORE key min max [WITHSCORES] [LIMIT offset count]
summary: Return a range of members in a sorted set, by score
since: 1.0.5

返回指定分数范围的成员，zrangebyscore按照从低到高返回，加上withscores，同时会返回成员的分数。[LIMIT offset count]选项可以限制输出的起始位置和个数。

同时min和max还支持开区间（小括号）和闭区间（中括号），-inf和+inf分别代表无限小和无限大

127.0.0.1:6379[1]> zrangebyscore k1 150 200 withscores
1) "chery"
2) "170"
3) "maek"
4) "200"
127.0.0.1:6379[1]> zrangebyscore k1 (100 +inf withscores
1) "tom"
2) "120"
3) "demeter"
4) "140"
5) "chery"
6) "170"
7) "maek"
8) "200

zrevrangebyscore

ZREVRANGEBYSCORE key max min [WITHSCORES] [LIMIT offset count]
summary: Return a range of members in a sorted set, by score, with scores ordered from high to low
ince: 2.2.0

与zrangebyscore相反，按照分值从高到低返回

127.0.0.1:6379[1]> zrevrangebyscore k1 200 100 withscores
1) "maek"
2) "200"
3) "chery"
4) "170"
5) "demeter"
6) "140"
7) "tom"
8) "120"

zcount

ZCOUNT key min max
summary: Count the members in a sorted set with scores within the given values
since: 2.0.0

返回指定分数范围成员个数

127.0.0.1:6379[1]> zcount k1 100 200
(integer) 4

zremrangebyrank

ZREMRANGEBYRANK key start stop
summary: Remove all members in a sorted set within the given indexes
since: 2.0.0

删除指定排名内的升序元素

127.0.0.1:6379[1]> zremrangebyrank k1 0 1
(integer) 2

zremrangebyscore

ZREMRANGEBYSCORE key min max
summary: Remove all members in a sorted set within the given scores
since: 1.2.0

删除指定分数范围的成员

127.0.0.1:6379[1]> zrange k1 0 -1 withscores
1) "demeter"
2) "140"
3) "chery"
4) "170"
5) "maek"
6) "200"
127.0.0.1:6379[1]> zremrangebyscore k1 200 +inf
(integer) 1
127.0.0.1:6379[1]> zrange k1 0 -1 withscores
1) "demeter"
2) "140"
3) "chery"
4) "170"

zinterstore

ZINTERSTORE destination numkeys key [key ...] [WEIGHTS weight] [AGGREGATE SUM|MIN|MAX]
summary: Intersect multiple sorted sets and store the resulting sorted set in a new key
since: 2.0.0

取交集

• destination：交际计算结果保存到这个键
• numkeys：需要做交集计算键的个数
• key [key …]：需要做交集的键
• [WEIGHTS weight]：每个键的权重，在做交集计算时，每个键中的每个member会将自己分数乘以这个权重，每个键的权重默认是1
• [AGGREGATE SUM|MIN|MAX]：计算成员交集后，分数可以按照sum、min、max做汇总，默认值是sum

127.0.0.1:6379[1]> zadd k2 12 a1 23 a2 31 a3 144 a4 230 a5
(integer) 5
127.0.0.1:6379[1]> zadd k3 18 a1 45 a3 54 a5 140 a7 123 a9
(integer) 5
127.0.0.1:6379[1]> ZINTERSTORE zinter 2 k2 k3
(integer) 3
127.0.0.1:6379[1]> zrange zinter 0 -1 withscores
1) "a1"
2) "30"
3) "a3"
4) "76"
5) "a5"
6) "284"

zunionstore

ZUNIONSTORE destination numkeys key [key ...] [WEIGHTS weight] [AGGREGATE SUM|MIN|MAX]
summary: Add multiple sorted sets and store the resulting sorted set in a new key
since: 2.0.0

取并集，参数与交集的参数一致

127.0.0.1:6379[1]> zunionstore zunion 2 k2 k3
(integer) 7
127.0.0.1:6379[1]> zrange zunion 0 -1 withscores
 1) "a2"
 2) "23"
 3) "a1"
 4) "30"
 5) "a3"
 6) "76"
 7) "a9"
 8) "123"
 9) "a7"
10) "140"
11) "a4"
12) "144"
13) "a5"
14) "284"

内部编码

• ziplist：当有序集合的元素个数小于zset-max-ziplist-entries配置（默认128个），同时每个元素的值都小于zset-max-ziplist-value配置时（默认64字节），Redis会选用ziplist来作为有序集合的内部实现来减少内存的使用

• skiplist（跳跃表）：当有序集合无法满足ziplist的条件时，使用skiplist作为有序集合的内部实现，因为此时ziplist的读写效率会下降

当元素个数较少且每个元素较小时，内部编码为ziplist

127.0.0.1:6379[1]> object encoding k2
"ziplist"

当元素个数超过128个，内部编码变为skiplist

127.0.0.1:6379[1]> zadd k4 1 a1 2 a2 3 a3 4 a4 ... 129 a129
127.0.0.1:6379[1]> object encoding k4
"skiplist"

当某个元素大于64字节时，内部编码变为skiplist

127.0.0.1:6379[1]> zadd k5 1 abababab................................................................................
127.0.0.1:6379[1]> object encoding k5
"skiplist"

应用

• 排行榜，例如博客用户的点赞数

1. 添加用户的点赞数

   tom在2020-12-15获得十个赞，在之后有获取一个赞

   127.0.0.1:6379[1]> zadd user:ranking:2020_12_15 10 tom
   (integer) 1
   127.0.0.1:6379[1]> zincrby user:ranking:2020_12_15 1 tom
   "11"
   

2. 取消用户赞数

   如果用户存在作弊，需要将用户删除

   127.0.0.1:6379[1]> zrem user:ranking:2020_12_15 tom 
   

3. 展示获取赞数最多的十个用户

   127.0.0.1:6379[1]> zrevrange user:ranking:2020_12_15 0 9
   1) "tom"
   

4. 展示用户信息以及用户表

   用户信息可以存在hash类型中

   127.0.0.1:6379[1]> hgetall user:info:tom
   127.0.0.1:6379[1]> zrank user:ranking:2020_12_15  tom
   (integer) 0
   127.0.0.1:6379[1]> zscore user:ranking:2020_12_15  tom
   "11"