set in Redis

How to work with set in Redis in [2022]

Redis is a popular open-source, Key-value type storage. In this blog, we will learn how to work with set in redis.

Redis set type

Redis set is an unordered collection of unique strings. In Redis, sets also do not allow the repetition of values in a key. In redis, we can perform many operations on sets like creating sets, retrieving data from sets, removing members from sets, etc.

Redis set command

In redis there any many sets of commands which a user can use to perform various operations. Below are the few SET commands present in redis.

SADD
SREM
SISMEMBER 
SINTER 
SINTER 

Redis set examples

redis set examples

In this session, we will understand how to effectively use various set commands in redis.

Creating Sets in redis

Using the SADD command a user can add a new member to the set. The syntax for the SADD command follows below the pattern.

SADD key member [member ...]

Let’s insert the key using the SADD command to insert 3 values in the set key

sadd key_1 value_1_1 value_1_2 value_1_3
Creating Sets in redis

Redis set get all members

Using smembers command we can retrieve all members from a set in redis.The syntax for smembers command follows the below pattern.

smembers key

Now let’s retrieve all keys present in key_1 member

smembers key_1
Redis set get all members

Removes a member from the set in redis

Redis also provides a facility to remove a particular member from a set using the SREM command. The syntax for the SREM command follows the below pattern.

SREM key member [member ...]

Let’s use the above command to remove member value_1_1 from key_1.

SREM key_1 value_1_1
Removes a member from the set in redis

Check the size of a set in redis

Using the redis SCARD command, a user can retrieve the number of elements of a set stored in a key.Let’s retrieve the elements present in key_1.

SCARD key_1
Check the size of a set in redis

Comparing Sets in redis

Redis also provides us the facility to compare various sets and return the interaction using the SINTER command. The SINTER command follows the below pattern.

SINTER key [key ...]

Below is a simple illustration of SINTER functionality.

key_1 = {p,q,r}
key_2 = {q}
key_3 = {p,q,s}
SINTER key_1 key_2 key_3 = {q}
Comparing Sets in redis

Redis set python

redis set python

A user can also use python to retrieve the sets stored in a redis instance. You can follow my tutorial on Redis python to configure a redis python instance in your environment.

Below is the code snipped to retrieve the members from key_1

import redis
r = redis.StrictRedis(host='localhost',port=6379, db=0)
r.smembers(key_1))

Conclusion

I hope you have liked this small tutorial on how to work with the set in redis. please do let me know if you are facing any issues while following along.

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