# 17.4.5 set类型

* ⽆序集合
* 元素为string类型
* 元素具有唯⼀性，不重复
* 说明：对于集合没有修改操作

增加

* 添加元素

sadd key member1 member2 ...

* 例1：向键'a3'的集合中添加元素'zhangsan'、'lisi'、'wangwu'

sadd a3 zhangsan sili wangwu

![Image](https://github.com/clay-wangzhi/wiki/tree/46b947765d64b8562206df9ac2bae98e26b90b86/17%20Redis/17.4%20数据库操作/images/df11040715a63f064757956a24c5d7df6f4bed53.png)

获取

* 返回所有的元素

smembers key

* 例2：获取键'a3'的集合中所有元素

smembers a3

![Image](https://github.com/clay-wangzhi/wiki/tree/46b947765d64b8562206df9ac2bae98e26b90b86/17%20Redis/17.4%20数据库操作/images/9ad9d7e260a7f33bf2d8ad74e1f4962dab096315.png)

删除

* 删除指定元素

srem key value

* 例3：删除键'a3'的集合中元素'wangwu'

srem a3 wangwu

![Image](https://github.com/clay-wangzhi/wiki/tree/46b947765d64b8562206df9ac2bae98e26b90b86/17%20Redis/17.4%20数据库操作/images/542cd7f4df873335ac556491b7c97b8450654e45.png)


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