Imagine you are developing a feature for an application that tracks **user interests**. Information about each user is stored in **Redis** as a **set**. Each user has a unique collection of **interests**.

1. Add the **interests** for each **user** to their respective **sets**:
    - `user:1:interests`: "**music**", "**movies**", "**sports**";
   - `user:2:interests`: "**sports**", "**travel**", "**reading**";
   - `user:3:interests`: "**reading**", "**music**", "**cooking**".

2. Check if **User 1** is interested in "**travel**" and if **User 2** is interested in "**sports**";
3. Identify the **common interests** of **User 1** and **User 2**;
4. Find the **interests** of **User 1** that are not shared by **User 2**;
5. Create a list of all **unique interests** shared by **User 1**, **User 2**, and **User 3**;
6. **User 3** has stopped being interested in "**music**." Remove this **interest** from their **set**;
7. Display the list of **interests** for each **user** after performing these operations.

**1**. Add **interests** for each **user** to their respective **sets**:

```
SADD user:1:interests "music" "movies" "sports"
SADD user:2:interests "sports" "travel" "reading"
SADD user:3:interests "reading" "music" "cooking"
```

<br>

**2**. Verify if a specific **interest** exists in a **user's set**:

```
SISMEMBER user:1:interests "travel"    # result: 0 (User 1 is not interested)
SISMEMBER user:2:interests "sports"   # result: 1 (User 2 is interested)
```

<br>

**3**. Retrieve **shared interests** between two **users**:

```
SINTER user:1:interests user:2:interests   # result: ["sports"]
```
<br>

**4**. Get **interests** of one **user** that are not shared by another:

```
SDIFF user:1:interests user:2:interests   # result: ["music", "movies"]
```

<br>

**5**. Create a full list of **unique interests** from all **users**:

```
SUNION user:1:interests user:2:interests user:3:interests   # result: ["music", "movies", "sports", "travel", "reading", "cooking"]
```

<br>

**6**. Delete an **interest** from a **user's set**:

```
SREM user:3:interests "music"
```
<br>

**7**. Retrieve the updated **sets** of **interests** for each **user**:

```
SMEMBERS user:1:interests   # result: ["music", "movies", "sports"]
SMEMBERS user:2:interests   # result: ["sports", "travel", "reading"]
SMEMBERS user:3:interests   # result: ["reading", "cooking"]
```

This course will introduce you to the fundamentals of Redis and its use in real-world applications. We'll cover key Redis commands, data types, key expiration and transactions, as well as how to integrate Redis with Spring for efficient data caching.

This section provides an introduction to Redis, highlighting its core features and common use cases. You’ll learn how to install Redis on different platforms, including Windows and macOS, and get familiar with the basics of connecting to and starting the Redis server.

Here, we explore the essential Redis commands for managing and manipulating data effectively. You'll learn how to set, retrieve, increment, and delete data using commands like SET, GET, EXISTS, INCR, DECR, and tackle practical tasks to apply these concepts in real-world scenarios.

Here, you will learn about key Redis data types, including Lists, Sets, Sorted Sets, and Hashes. You will explore their functionality and practical applications through focused exercises designed to reinforce your understanding of each data type.

You'll explore advanced features of Redis, including managing key lifecycles, executing transactions, and leveraging the Pub/Sub messaging system. Additionally, you'll learn essential security practices to safeguard your Redis environment against unauthorized access.

This section introduces the fundamentals of caching and demonstrates how to configure Redis as a cache in a Spring application. It covers key caching annotations and practical examples of caching queries in web applications, concluding with a summary of the main concepts.

Introduction to Redis

Challenge: Managing User Interests