Strutture dati fondamentali di Redis

Redis offers real data structures, not just plain keys. We start with Strings: a value up to 512 MB holding text, JSON, or binary — like a persistent variable.

Store and read a String with SET and GET. The code below sets a couple of keys and fetches them back.

Redis Hashes are like objects: many field-value pairs under one key. Perfect for modeling things like a user profile with several attributes.

Use HSET to set fields in a hash, HGETALL to read them all, and HGET for a single field. The code below builds and reads a user hash.

Redis Lists are ordered string collections — push or pop from either end. Great for queues, stacks, and recent-activity feeds that keep insertion order.

LPUSH adds to the head, RPUSH to the tail, and LRANGE reads a range (0 -1 means everything). The code below pushes and lists items.

Redis Sets are unordered collections of unique strings — duplicates are silently ignored. Ideal for unique visitors, tags, or friendships.

SADD adds members (dupes ignored), SMEMBERS lists them all, and SISMEMBER checks membership. The code below demonstrates all three.

Redis Sorted Sets pair each unique member with a score and keep them ordered by it — perfect for leaderboards, rankings, and priority queues.

ZADD adds scored members, ZRANGE reads a range (add WITHSCORES to see scores), and ZSCORE gets one member's score. See the code below.

Recap: Redis data structures — Strings for basics, Hashes for objects, Lists for ordered queues, Sets for unique items, Sorted Sets for ranked data.