Redis Collection (Set)

Redis Collection (Set)

Redis's Set is a disordered collection of string types. C ollection members are unique, which means that duplicate data cannot occur in the collection.

Collections in Redis are implemented through hash tables, so add, delete, and find are all O(1).

The largest number of members in a ^{collection is 2 32 - 1} (4294967295, each of which can store more than 4 billion members).

Instance

redis 127.0.0.1:6379> SADD w3ckey redis
(integer) 1
redis 127.0.0.1:6379> SADD w3ckey mongodb
(integer) 1
redis 127.0.0.1:6379> SADD w3ckey mysql
(integer) 1
redis 127.0.0.1:6379> SADD w3ckey mysql
(integer) 0
redis 127.0.0.1:6379> SMEMBERS w3ckey

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

In the above example, we insert three elements into a collection named w3ckey through the SADD command.

Redis collection command

The following table lists the basic commands for the Redis collection: