Redis的常用命令——set

set的简单命令

set是会去重的集合,下面是一些操作set的常用命令

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

添加一个或多个元素

SMEMBERS key
summary: Get all the members in a set

取出set中的所有值。（一般不建议使用，占io）

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

获取集合中的成员数量

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

移除一个或多个元素

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

把一个元素从一个集合移动到目标集合

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

随机取出count个元素。（count为正返回不重复元素，count超出集合数量也只返回已有个数的元素。count为负返回可重复的元素，不限个数。）

交集并集差集的命令

redis提供了获取交并差集的操作

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

获取多个集合的交集

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

把多个集合的交集存放在目标集合。（直接在redis本地生成交集集合,较少io）

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

获取并集数据

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

把并集数据保存在目标集合

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

获取差集数据。（第一个集合（与后面集合不同的数据）减去与后面各集合的交集）

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

把差集数据保存在目标集合