redis基本数据类型Set

一、常用命令

集合类型也是用来保存多个字符串的元素，但和列表不同的是集合中

1. 不允许有重复的元素，
2. 集合中的元素是有序的，不能通过索引下标获取元素，
3. 支持集合间的操作，可以取多个集合取交集、并集、差集。
   

实战场景;

1. 标签：比如我们博客网站常常使用到的兴趣标签，把一个个有着相同爱好，关注类似内容的用户利用一个标签把他们进行归并。

2. 共同好友功能，共同喜好，或者可以引申到二度好友之类的扩展应用。

3. 统计网站的独立IP。利用set集合当中元素不唯一性，可以快速实时统计访问网站的独立IP。

1.1 添加

127.0.0.1:6379> sadd demoset 10
(integer) 1
127.0.0.1:6379> smembers demoset
1) "1"
2) "2"
3) "3"
4) "4"
5) "5"
6) "10"
127.0.0.1:6379> sadd demoset 8
(integer) 1
127.0.0.1:6379> smembers demoset
1) "1"
2) "2"
3) "3"
4) "4"
5) "5"
6) "8"
7) "10"

1.2 集合个数

127.0.0.1:6379> smembers demoset
1) "1"
2) "2"
3) "3"
4) "4"
127.0.0.1:6379> scard demoset
(integer) 4

1.3 查询

127.0.0.1:6379> smembers demoset
1) "1"
2) "2"
3) "3"
4) "4"

1.4 判断是否集合元素

127.0.0.1:6379> smembers demo1
1) "q"
127.0.0.1:6379> sismember demo1 q
(integer) 1
127.0.0.1:6379> sismember demo1 w
(integer) 0

1.5 差集

127.0.0.1:6379> smembers demoset
1) "1"
2) "2"
3) "3"
4) "4"
127.0.0.1:6379> smembers 1set
1) "3"
2) "r"
3) "e"
4) "2"
127.0.0.1:6379> sdiff demoset 1set
1) "1"
2) "4"

127.0.0.1:6379> smembers demo1
1) "1"
2) "2"
3) "3"
127.0.0.1:6379> smembers demo2
1) "e"
2) "w"
3) "q"
127.0.0.1:6379> smembers demo3
1) "d"
2) "g"
3) "q"
127.0.0.1:6379> sdiffstore demo1 demo2 demo3
(integer) 2
127.0.0.1:6379> smembers demo1
1) "e"
2) "w"

1.6 交集

127.0.0.1:6379> smembers demo2
1) "e"
2) "w"
3) "q"
127.0.0.1:6379> smembers demo3
1) "d"
2) "g"
3) "q"
127.0.0.1:6379> sinter demo2 demo3
1) "q"

127.0.0.1:6379> smembers demo1
1) "e"
2) "w"
127.0.0.1:6379> smembers demo2
1) "e"
2) "w"
3) "q"
127.0.0.1:6379> smembers demo3
1) "d"
2) "g"
3) "q"
127.0.0.1:6379> sinterstore demo1 demo2 demo3
(integer) 1
127.0.0.1:6379> smembers demo1
1) "q"

1.7 并集

127.0.0.1:6379> smembers songs
1) "Billie Jean"

127.0.0.1:6379> smembers my_songs
1) "Believe Me"

127.0.0.1:6379> sunion songs my_songs
1) "Billie Jean"
2) "Believe Me"

127.0.0.1:6379> smembers demo1
1) "q"
127.0.0.1:6379> smembers demo2
1) "e"
2) "w"
3) "q"
127.0.0.1:6379> smembers demo3
1) "d"
2) "g"
3) "q"
127.0.0.1:6379> sunionstore demo1 demo2 demo3
(integer) 5
127.0.0.1:6379> smembers demo1
1) "q"
2) "w"
3) "e"
4) "d"
5) "g"

1.8 值移动

127.0.0.1:6379> smembers k1
1) "1"
2) "2"
3) "3"
127.0.0.1:6379> smembers k2
1) "e"
2) "w"
3) "q"
127.0.0.1:6379> smove k1 k2 2
(integer) 1
127.0.0.1:6379> smembers k1
1) "1"
2) "3"
127.0.0.1:6379> smembers k2
1) "e"
2) "2"
3) "w"
4) "q"

1.9 随机删除

127.0.0.1:6379> smembers db
1) "MySQL"
2) "MongoDB"
3) "Redis"
127.0.0.1:6379> spop db
"Redis"
127.0.0.1:6379> smembers db
1) "MySQL"
2) "MongoDB"

1.10 随机返回

127.0.0.1:6379> sadd fruit apple banana cherry
(integer) 3

# 只给定 key 参数，返回一个随机元素

127.0.0.1:6379> srandmember fruit
"cherry"

127.0.0.1:6379> srandmember fruit
"apple"

# 给定 3 为 count 参数，返回 3 个随机元素
# 每个随机元素都不相同

127.0.0.1:6379> srandmember fruit 3
1) "apple"
2) "banana"
3) "cherry"

# 给定 -3 为 count 参数，返回 3 个随机元素
# 元素可能会重复出现多次

127.0.0.1:6379> srandmember fruit -3
1) "banana"
2) "cherry"
3) "apple"

1.11 删除

127.0.0.1:6379> smembers languages
1) "c"
2) "lisp"
3) "python"
4) "ruby"

# 移除单个元素

127.0.0.1:6379> srem languages ruby
(integer) 1


# 移除不存在元素

127.0.0.1:6379> srem languages non-exists-language
(integer) 0


# 移除多个元素

127.0.0.1:6379> srem languages lisp python c
(integer) 3

127.0.0.1:6379> smembers languages
(empty list or set)