Redis Set

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

The encoding of a set object can be intset or hashtable.

In Redis, sets are implemented via hash tables, so the complexity of add, delete, and lookup is O(1).

The maximum number of members in a set is 2^32³²-1 (4294967295, each set can store over 4 billion members).

Example

redis 127.0.0.1:6379> SADD examplekey redis
(integer) 1
redis 127.0.0.1:6379> SADD examplekey mongodb
(integer) 1
redis 127.0.0.1:6379> SADD examplekey mysql
(integer) 1
redis 127.0.0.1:6379> SADD examplekey mysql
(integer) 0
redis 127.0.0.1:6379> SMEMBERS examplekey

1) "mysql"
2) "mongodb"
3) "redis"

In the above example, weSADDuse the command to insert into the namedexamplekeyset three elements.

Redis Set Commands

The following table lists the basic Redis Set commands: