redis之Set集合數據類型以及存儲原理

1.概述

1.1.無順序

1.2.不可以重複

1.3.最大存儲2^32-1（40億）個key數量

2.常用命令 :http://redisdoc.com/set/index.html

2.1.添加一個或者多個value:sadd friends gaoxinfu zhaoboluns

127.0.0.1:6379> sadd friends gaoxinfu zhaoboluns
(integer) 2
127.0.0.1:6379> 

2.2.列出所有的values:SMEMBERS friends

127.0.0.1:6379> SMEMBERS friends
1) "zhaoboluns"
2) "gaoxinfu"
127.0.0.1:6379> 

2.2.統計數組的長度(value個數)：SCARD friends

127.0.0.1:6379> SCARD friends
(integer) 2
127.0.0.1:6379> 

2.3.隨機獲取一個value(但是並不刪除)：srandmember friends

127.0.0.1:6379> SMEMBERS friends
1) "zhaoboluns"
2) "gaoxinfu"
127.0.0.1:6379> srandmember friends
"gaoxinfu"
127.0.0.1:6379> 
127.0.0.1:6379> SMEMBERS friends
1) "zhaoboluns"
2) "gaoxinfu"
127.0.0.1:6379> 

2.4.隨機彈出一個value(彈出的value被刪除)：spop friends

127.0.0.1:6379> spop friends
"zhaoboluns"
127.0.0.1:6379> SMEMBERS friends
1) "gaoxinfu"
127.0.0.1:6379> 

2.5.刪除一個或多個value：srem friends gaoxinfu1 gaoxinfu3

127.0.0.1:6379> SMEMBERS friends
1) "gaoxinfu1"
2) "gaoxinfu3"
3) "gaoxinfu2"
4) "gaoxinfu"
5) "gaoxinfu4"
127.0.0.1:6379> srem friends gaoxinfu1 gaoxinfu3
(integer) 2
127.0.0.1:6379> SMEMBERS friends
1) "gaoxinfu"
2) "gaoxinfu2"
3) "gaoxinfu4"
127.0.0.1:6379> 

2.6.判斷value是否存在：sismember friends gaoxinfu

127.0.0.1:6379> SMEMBERS friends
1) "gaoxinfu"
2) "gaoxinfu2"
3) "gaoxinfu4"
127.0.0.1:6379> sismember friends gaoxinfu3
(integer) 0
127.0.0.1:6379> sismember friends gaoxinfu
(integer) 1
127.0.0.1:6379> 

3.存儲原理

4.應用場景

4.1.點贊:將點讚的人userId 進行sadd,取消點贊則 srem

4.2.抽獎：隨機彈出spop

4.3.簽到，用戶關注

4.4.購物標籤