Redis Sets (Set)

Redis's Set is an unordered collection of String type. Set members are unique, which means that duplicate data cannot appear in the set.

Redis sets are implemented through hash tables, so the complexity of adding, deleting, and searching is O(1)

The maximum number of members in the set is 2³² 　- 1 (4294967295, each set can store4With over 0 billion members).

Online examples

redis　127.0.0.1:6379> SADD w3codeboxkey redis
(integer)　1
redis　127.0.0.1:6379> SADD w3codeboxkey mongodb
(integer)　1
redis　127.0.0.1:6379> SADD w3codeboxkey mysql
(integer)　1
redis　127.0.0.1:6379> SADD w3codeboxkey mysql
(integer) 0
redis　127.0.0.1:6379> SMEMBERS w3codeboxkey
1) "mysql"
2) "mongodb"
3) "redis"

In the above example, we use SADD The command adds to the set named w3codeboxkey Three elements inserted into the set.

Redis set commands

The following table lists the basic Redis set commands: