Summary  
This chapter introduces lists as mutable ordered collections in code, demonstrating how to store, access by index, and modify elements by adding or removing items.

General domain of usage  
Game inventory management

Python lists are like containers that can hold different items. You can create a list by enclosing items in square brackets `[]`:

```python
list_ = ["cat", "dog", "chicken", "monkey"]

In the Ninja Game, you can interact with the list using the following methods:

- `pick_to_inventory(index)`: picks up an item and places it in the inventory at the specified `index`, or adds it to the end of the list (or the first element if the list is empty) if no `index` is provided;
- `put_from_inventory(index)`: takes an item from the inventory by `index` and places it on the map. If no `index` is provided, it takes the last item.

Here is an example where the Ninja collects 2 animals into the inventory and then places the first element back on the map.
> Note
>
> In Python, counting starts from 0.

> Note
>
> In this course, you do not need to define lists yourself — they are already built into the code logic.

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When you run the code on the map, you will see a purple bar at the top — this is your **inventory**.

Welcome to the Python Ninja Course! This engaging and interactive course is designed to introduce you to the fundamentals of Python programming through a fun and educational game. You will guide a Ninja through various challenges, using Python to control movements and interact with objects like sushi. Starting with the basics, you will learn how to navigate the map, pick up and place sushi, and gradually progress to more complex programming concepts such as functions, loops, and conditional statements. Each chapter offers hands-on practice to reinforce your learning, culminating in exciting challenges that test your skills. Whether you are a complete beginner or looking to sharpen your coding abilities, this course provides a comprehensive and enjoyable learning experience. Join us and become a coding Ninja!

In the "Basic Controls" section, you will be introduced to the foundational features of Python through the engaging Ninja Game. You'll learn how to use Python commands to control your Ninja's movements and interactions on the grid, mastering essential functions like moving, picking up, and placing sushi. Through hands-on practice, you'll apply these skills to solve fun challenges, reinforcing your understanding of Python's basic capabilities.

In the "Advanced Controls" section, you will build on the skills you learned earlier and gain more control over the Ninja's movement. You'll learn how to navigate longer paths, handle turns and obstacles, and combine multiple actions into more efficient movement patterns. Through practice, you will develop better control logic and start thinking ahead, preparing you for more complex challenges later in the game.

In the "Functions" section, you will delve into the powerful Python feature of creating and utilizing functions to streamline your code. You will learn how to write functions to perform specific tasks, enhancing code reusability and clarity. By practicing decomposition, you will break down complex problems into simpler functions, mastering the art of organized and efficient coding.

In the "Loops" section, you will explore the essential Python feature of loops, which allows you to execute repetitive tasks efficiently. You will learn to implement both for loops and while loops, gaining the ability to automate actions and iterate over sequences. By mastering nested loops, you will tackle more complex scenarios, enhancing your ability to write concise and powerful code.

In the "If-Else Statements" section, you will learn how to use Python's conditional logic to make decisions within your code. You will explore how if-else statements allow your ninja to respond dynamically to different scenarios, enabling more intelligent and adaptable behavior. Through practical exercises, you will apply these concepts to solve challenges, enhancing your ability to write responsive and decision-driven code.

In the "Lists" section, you will learn how lists enable you to store multiple items, perform operations, and manage data efficiently. Through practical exercises, you will apply these concepts to solve challenges, improving your ability to write organized and dynamic code for handling collections of information.

In the "Challenges" section, you will apply your Python skills to tackle a series of engaging and complex problems. These challenges will test your understanding of loops, functions, and conditional logic as you guide your ninja to align columns, build letters, and traverse intricate patterns. By solving these puzzles, you will refine your coding abilities and gain confidence in applying Python to creative and real-world scenarios.

Introduction to Lists

Solution