Redis Guide: The High-Speed In-Memory Data Store

It’s time to explore Redis (REmote DIctionary Service), a high-speed, in-memory NoSQL data store. Redis is often called a ‘data structure server’ because it can store and manipulate different data types like strings, lists, sets, and hashes, not just simple key-value pairs. Because it keeps its entire dataset in RAM, Redis is exceptionally fast, making it a popular choice for caching, real-time analytics, and message queues.

💻 Redis Data Types

Redis’s power comes from its versatile data types. The most common include:

• Strings: The most basic type, which can store text or binary data up to 512MB.
• Lists: A list of strings, sorted by insertion order. You can push elements to the head (LPUSH) or tail (RPUSH).
• Sets: An unordered collection of unique strings. You can perform powerful operations like unions and intersections.
• Hashes: A map between string fields and string values, perfect for storing objects.
• Sorted Sets: Similar to sets, but each member has an associated score, which is used to keep the set ordered.

💻 Interacting with Redis via CLI

You can interact with Redis directly from your terminal using the redis-cli tool. It provides an interactive shell for running commands.

# Start the Redis client
$ redis-cli
127.0.0.1:6379>

# Set a string value
127.0.0.1:6379> SET aKey "Mihalis"
OK

# Get a string value
127.0.0.1:6379> GET aKey
"Mihalis"

# Push items to a list
127.0.0.1:6379> LPUSH aList "123"
(integer) 1
127.0.0.1:6379> RPUSH aList "Tsoukalos"
(integer) 2

# Get a range of items from a list
127.0.0.1:6379> LRANGE aList 0 -1
1) "123"
2) "Tsoukalos"

💻 Using Redis with Python

To use Redis in your Python applications, you’ll need to install the official client library. The code is simple and maps directly to the Redis commands.

1. Install the Library:
   pip install redis
2. Connect and Use in Python:
   

   import redis
   
   # Connect to the Redis server
   r = redis.StrictRedis(host='localhost', port=6379, db=0)
   
   # Set and get a value
   r.set('One', 'Two')
   myVal = r.get('One')
   
   # rpush returns the new length of the list
   r.rpush('telephone', '123', 'Mihalis', 'Tsoukalos')
   
   # lrange returns a list of values
   aList = r.lrange('telephone', 0, -1)
   print(aList)

   
   

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