set

命令

• SADD:
• SMEMBERS:
• SREM:
• SCARD:
• SISMEMBER:
• SRANDMEMBER:
• SPOP:
• SINTER:
• SUNION:
• SDIFF:
• SINTERSTORE:
• SUNIONSTORE:
• SDIFFSTORE:

示例

创建集合键

127.0.0.1:6379> SADD myset2 1 2 3 4 5
(integer) 5

获取集合键中的元素

127.0.0.1:6379> SMEMBERS myset2
1) "1"
2) "2"
3) "3"
4) "4"
5) "5"

删除集合键中指定元素

127.0.0.1:6379> SREM myset2 5
(integer) 1
127.0.0.1:6379> SMEMBERS myset2
1) "1"
2) "2"
3) "3"
4) "4"

随即删除集合键中一个元素

127.0.0.1:6379> SPOP myset2
"1"
127.0.0.1:6379> SPOP myset2
"4"
127.0.0.1:6379> SPOP myset2
"2"
127.0.0.1:6379> SPOP myset2
"3"

获取集合键的元素个数

127.0.0.1:6379> SADD myset2 1 2 3 4
(integer) 4
127.0.0.1:6379> SCARD myset2
(integer) 4

判断集合键中是否存在特定值的元素

127.0.0.1:6379> SISMEMBER myset2 4
(integer) 1
127.0.0.1:6379> SISMEMBER myset2 5
(integer) 0

随机返回集合键中指定数量的元素

127.0.0.1:6379> SRANDMEMBER myset2
"1"
127.0.0.1:6379> SRANDMEMBER myset2 2
1) "1"
2) "4"

获取多个集合键的交集元素

127.0.0.1:6379> SADD myset1 Music Game Sport
(integer) 3
127.0.0.1:6379> SADD myset2 Music Coding
(integer) 2
127.0.0.1:6379> SADD myset3 Music Writing
(integer) 2
127.0.0.1:6379> SINTER myset1 myset2 
1) "Music"
127.0.0.1:6379> SINTER myset1 myset2 myset3
1) "Music"

获取多个集合键中元素的并集

127.0.0.1:6379> SUNION myset1 myset2 myset3
1) "Music"
2) "Writing"
3) "Coding"
4) "Sport"
5) "Game"

获取多个集合键中元素的差集

PS: 位置不同得到的结果不同

127.0.0.1:6379> SDIFF myset1 myset2 myset3
1) "Game"
2) "Sport"

由于Redis进行交集、并集、差集计算相对来说比较耗费性能，所以建议将元素过多且通用的结果保存起来，以避免不必要的性能开销

保存多个集合键的交集

127.0.0.1:6379> SINTERSTORE myset_1_2_3_inter myset1 myset2 myset3
(integer) 1
127.0.0.1:6379> SMEMBERS myset_1_2_3_inter
1) "Music"

保存多个集合键的并集

127.0.0.1:6379> SUNIONSTORE myset_1_2_3_union myset1 myset2 myset3
(integer) 5
127.0.0.1:6379> SMEMBERS myset_1_2_3_union
1) "Music"
2) "Writing"
3) "Coding"
4) "Sport"
5) "Game"

保存多个集合键的差集

127.0.0.1:6379> SDIFFSTORE myset_1_2_3_diff myset1 myset2 myset3
(integer) 2
127.0.0.1:6379> SMEMBERS myset_1_2_3_diff
1) "Game"
2) "Sport"

内部编码

• intset: 当集合键内元素都是整数，并且元素个数小于set-max-intset-entries(默认512)时，会使用intset作为内部编码
• hashtable: 当集合键元素不满足intset条件时，会使用hashtable作为内部编码

应用场景

标签

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