Redis Ordered Collection (sorted set)

Redis Ordered Collection (sorted set)

Redis ordered collections, like collections, are collections of string type elements and do not allow duplicate members.

The difference is that each element is associated with a double type score. I t is through fractions that redis sorts members of a collection from small to large.

The members of the ordered collection are unique, but the score can be repeated.

Collections are implemented through hash tables, so adding, deleting, and finding are all O(1). T he 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> ZADD w3ckey 1 redis
(integer) 1
redis 127.0.0.1:6379> ZADD w3ckey 2 mongodb
(integer) 1
redis 127.0.0.1:6379> ZADD w3ckey 3 mysql
(integer) 1
redis 127.0.0.1:6379> ZADD w3ckey 3 mysql
(integer) 0
redis 127.0.0.1:6379> ZADD w3ckey 4 mysql
(integer) 0
redis 127.0.0.1:6379> ZRANGE w3ckey 0 10 WITHSCORES

1) "redis"
2) "1"
3) "mongodb"
4) "2"
5) "mysql"
6) "4"

In the above example, we added three values to the ordered collection of redis by commanding ZADD and associated the score.

Redis ordered collection commands

The following table lists the basic commands for the redis ordered collection: