Redis is a versatile in-memory data structure store that supports various data types. Understanding these basic data types is crucial for effectively using Redis in your applications. In this section, we will cover the following Redis data types:

1. Strings
2. Lists
3. Sets
4. Hashes
5. Sorted Sets

Strings are the most basic Redis data type. They are binary-safe, meaning they can contain any kind of data, such as text, numbers, or serialized objects.

• SET mykey "Hello, Redis!": This command sets the value of the key mykey to "Hello, Redis!".
• GET mykey: This command retrieves the value associated with the key mykey.

1. Set a key username with the value john_doe.
2. Retrieve the value of the key username.

Solution:

Lists are ordered collections of strings. You can add elements to the head or the tail of the list.

• LPUSH mylist "world": This command pushes the value "world" to the head of the list mylist.
• LPUSH mylist "hello": This command pushes the value "hello" to the head of the list mylist.
• LRANGE mylist 0 -1: This command retrieves all elements in the list mylist.

1. Create a list colors and add the elements red, green, and blue.
2. Retrieve all elements from the list colors.

Solution:

Sets are unordered collections of unique strings. They are useful for storing unique elements.

• SADD myset "apple": This command adds the value "apple" to the set myset.
• SADD myset "banana": This command adds the value "banana" to the set myset.
• SADD myset "apple": This command attempts to add "apple" again, but since sets only store unique values, it will not be added.
• SMEMBERS myset: This command retrieves all members of the set myset.

1. Create a set fruits and add the elements apple, orange, and banana.
2. Retrieve all elements from the set fruits.

Solution:

Hashes are collections of key-value pairs, where each key is associated with a value. They are useful for representing objects.

• HSET user:1000 name "John Doe": This command sets the field name of the hash user:1000 to "John Doe".
• HSET user:1000 email "[email protected]": This command sets the field email of the hash user:1000 to "[email protected]".
• HGETALL user:1000: This command retrieves all fields and values of the hash user:1000.

1. Create a hash product:2000 with fields name set to Laptop and price set to 1200.
2. Retrieve all fields and values from the hash product:2000.

Solution:

Sorted Sets are similar to sets but with an associated score for each member. Members are ordered by their scores.

• ZADD leaderboard 100 "player1": This command adds the member "player1" with a score of 100 to the sorted set leaderboard.
• ZADD leaderboard 200 "player2": This command adds the member "player2" with a score of 200 to the sorted set leaderboard.
• ZRANGE leaderboard 0 -1 WITHSCORES: This command retrieves all members and their scores from the sorted set leaderboard.

1. Create a sorted set scores and add the elements alice with a score of 50 and bob with a score of 75.
2. Retrieve all elements and their scores from the sorted set scores.

Solution:

In this section, we covered the basic Redis data types: Strings, Lists, Sets, Hashes, and Sorted Sets. Each data type has its unique characteristics and use cases. Understanding these data types is fundamental to effectively using Redis in your applications. In the next module, we will delve deeper into each data structure and explore their advanced features and operations.