Redis笔记（set）

猫子哥

Feb 20·5 min read

127.0.0.1:6379> help @set

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

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

  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

  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

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

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

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

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

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

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

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

  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

SADD命令用来创建一个set并添加值

SCARD命令用来查询一个set里的成员数量

SMEMBERS用来获取一个set中所有的成员的值（注意：如果set很大，这个命令会消耗Redis主机的网卡吞吐量）

SREM可以删除set中的成员(支持移除多个)

使用set可以进行交集，并集，差集的操作

比如现在有两个set，set1中有1,2,3,4,5，set2中有4,5,6,7,8

使用SINTER命令可以返回交集

使用SINTERSTORE可以把交集存储到一个目标key中

SUNION取并集同理

SDIFF可以取差集，返回的是第一个key集合中有，而第二个key没有的成员

使用SRANDMEMBER命令可以随意取值，从一个key中随机取值，如果参数count是正，取出一组不重复的结果，如果参数count是负数，取出这个数绝对值个的结果（如果范围超过set长度，值可重复），为0返回空。

还有一种随机取值可以将set中的值pop出来，就是SPOP命令，会从set中随机取值并从set中删除这个成员