Quest 5: Lists - Collecting Treasures

Learn to Organize Multiple Items in Python

📜 QUEST 5 | Difficulty: Beginner | Time: 5 minutes

📊 Complexity Level: Beginner ⭐

Perfect for students with no programming experience. This lesson introduces fundamental concepts that are essential for all programming. Great for college fair visitors and first-time coders!

💻 Interactive Options:

📓 Open in JupyterLite - Full Jupyter environment in your browser
▶️ Run code directly below - All code cells on this page are editable and runnable
📥 Download Notebook - For use in local Jupyter or Google Colab

📖 Introduction: The Treasure Chest

You’re collecting items on your adventure: a sword, a shield, three health potions, a map, and a mysterious key. How do you keep track of everything?

You could use separate variables:

item1 = "sword"
item2 = "shield"
item3 = "health potion"
# This gets messy fast! 😵

Or you could use a list - a single container that holds all your items in order!

🎒 Story Time: Think of a list like your adventure backpack. It holds multiple items, keeps them in order, and you can add or remove things as you go. You can even check what’s at specific positions, like “What’s in pocket number 3?”

💡 Explanation: What are Lists?

A list is an ordered collection of items. Lists are: - Created with square brackets [] - Can hold different types of data - Items are ordered and indexed (starting from 0!) - Mutable (you can change them)

# Creating lists
inventory = ["sword", "shield", "potion"]
scores = [100, 95, 87, 92]
mixed = [1, "hello", True, 3.14]
empty = []

📊 List Indexing:

Items in a list have positions (indices) starting from 0:

fruits = ["apple", "banana", "cherry", "date"]
#         0        1         2         3

Access items: Negative indices count from the end:

print(fruits[0])   # "apple"
print(fruits[2])   # "cherry"
print(fruits[-1])  # "date" (last item)
print(fruits[-2])  # "cherry" (second from end)

🎮 Activity: Manage Your Inventory

Let’s create and manipulate an adventure inventory:

🎯 Challenge:

Add a “magic wand” to the inventory
Remove the “rope” using inventory.remove("rope")
Insert a “compass” at position 1 using inventory.insert(1, "compass")
Print the total number of items

👨‍💻 Code Example: List Operations

Lists have many useful methods and operations:

💡 Common List Methods:

list.append(item) - Add item to end
list.remove(item) - Remove first occurrence
list.pop() - Remove and return last item
list.insert(index, item) - Insert at position
list.sort() - Sort the list in place
list.reverse() - Reverse the list in place
len(list) - Get number of items

🧩 Puzzle Time!

What will this code produce? Think through it, then run:

🔑 Solution Explained:

The final list is: [5, 10, 20, 40, 50]

Step-by-step trace:

Start: [10, 20, 30, 40, 50]
After append(60): [10, 20, 30, 40, 50, 60]
- Adds 60 to the end
After insert(0, 5): [5, 10, 20, 30, 40, 50, 60]
- Inserts 5 at position 0 (beginning)
After remove(30): [5, 10, 20, 40, 50, 60]
- Removes the first occurrence of 30
After pop(): [5, 10, 20, 40, 50]
- Removes the last item (60)

Key insight: Each method modifies the list in place. The order of operations matters!

🎮 Bonus: Slicing Lists

You can extract portions of a list using slicing:

🎯 Key Takeaways

✨ Quest 5 Complete! ✨

You’ve learned:

✅ Lists store multiple items in order
✅ Lists are indexed starting from 0
✅ Use methods like append(), remove(), pop(), insert()
✅ Access items with bracket notation: list[index]
✅ Lists can be sliced, sorted, and reversed
✅ Use len(), max(), min(), sum() for analysis

Next Quest: Ready to create reusable code? Try Quest 6: Functions!

🚀 Try This at Home!

Create a to-do list manager:

# Simple to-do list
tasks = ["Learn Python", "Build a game", "Read a book"]

print("MY TO-DO LIST")
for i, task in enumerate(tasks, 1):
    print(f"{i}. {task}")

# Add new task
tasks.append("Practice coding")

# Mark a task as done (remove it)
completed = tasks.pop(0)
print(f"\nCompleted: {completed}")
print(f"Remaining: {tasks}")

Or make a high score tracker:

high_scores = [1500, 1200, 1000, 950, 800]
new_score = 1100

high_scores.append(new_score)
high_scores.sort(reverse=True)
high_scores = high_scores[:5]  # Keep only top 5

print("Top 5 High Scores:")
for rank, score in enumerate(high_scores, 1):
    print(f"{rank}. {score} points")

📱 Excellent Progress! Lists are essential in almost every program. Master them! 📋

--- title: "Quest 5: Lists - Collecting Treasures" subtitle: "Learn to Organize Multiple Items in Python" format: live-html: code-tools: true --- ::: {.quest-badge} 📜 QUEST 5 | Difficulty: Beginner | Time: 5 minutes ::: ::: {.concept-box} **📊 Complexity Level: Beginner ⭐** Perfect for students with **no programming experience**. This lesson introduces fundamental concepts that are essential for all programming. Great for college fair visitors and first-time coders! ::: ::: {.tip-box} **💻 Interactive Options:** - 📓 **[Open in JupyterLite](../jupyterlite/lab/index.html?path=05-lists.ipynb)** - Full Jupyter environment in your browser - ▶️ **Run code directly below** - All code cells on this page are editable and runnable - 📥 **[Download Notebook](../files/lessons/05-lists.ipynb)** - For use in local Jupyter or Google Colab ::: ## 📖 Introduction: The Treasure Chest You're collecting items on your adventure: a sword, a shield, three health potions, a map, and a mysterious key. How do you keep track of everything? You could use separate variables: ```python item1 = "sword" item2 = "shield" item3 = "health potion" # This gets messy fast! 😵 ``` Or you could use a **list** - a single container that holds all your items in order! ::: {.story-box} **🎒 Story Time**: Think of a list like your adventure backpack. It holds multiple items, keeps them in order, and you can add or remove things as you go. You can even check what's at specific positions, like "What's in pocket number 3?" ::: ## 💡 Explanation: What are Lists? A **list** is an ordered collection of items. Lists are: - Created with square brackets `[]` - Can hold different types of data - Items are ordered and indexed (starting from 0!) - Mutable (you can change them) ```python # Creating lists inventory = ["sword", "shield", "potion"] scores = [100, 95, 87, 92] mixed = [1, "hello", True, 3.14] empty = [] ``` ::: {.concept-box} **📊 List Indexing**: Items in a list have positions (indices) starting from 0: ```python fruits = ["apple", "banana", "cherry", "date"] # 0 1 2 3 ``` Access items: **Negative indices count from the end**: ```python print(fruits[0]) # "apple" print(fruits[2]) # "cherry" print(fruits[-1]) # "date" (last item) print(fruits[-2]) # "cherry" (second from end) ``` ::: ## 🎮 Activity: Manage Your Inventory Let's create and manipulate an adventure inventory: ```{pyodide-python} # Start with some basic items inventory = ["torch", "rope", "map"] print("=== INVENTORY SYSTEM ===") print(f"Starting inventory: {inventory}") print(f"Number of items: {len(inventory)}") print() # Add items inventory.append("health potion") print("Found a health potion!") print(f"Updated inventory: {inventory}") print() # Add multiple items at once inventory.extend(["sword", "shield"]) print("Equipped sword and shield!") print(f"Updated inventory: {inventory}") print() # Access specific items print(f"First item: {inventory[0]}") print(f"Last item: {inventory[-1]}") print(f"Third item: {inventory[2]}") print() # Remove items used_item = inventory.pop() # Removes and returns last item print(f"Removed: {used_item}") print(f"Current inventory: {inventory}") # Try changing the starting items or adding different ones! ``` ::: {.challenge-box} **🎯 Challenge**: 1. Add a "magic wand" to the inventory 2. Remove the "rope" using `inventory.remove("rope")` 3. Insert a "compass" at position 1 using `inventory.insert(1, "compass")` 4. Print the total number of items ::: ## 👨‍💻 Code Example: List Operations Lists have many useful methods and operations: ```{pyodide-python} # Battle scores scores = [85, 92, 78, 95, 88] print("=== SCORE TRACKER ===") print(f"All scores: {scores}") print() # Statistics print(f"Highest score: {max(scores)}") print(f"Lowest score: {min(scores)}") print(f"Total points: {sum(scores)}") print(f"Average: {sum(scores) / len(scores):.2f}") print() # Sorting scores_sorted = sorted(scores) # Returns new sorted list print(f"Sorted (ascending): {scores_sorted}") print(f"Sorted (descending): {sorted(scores, reverse=True)}") print() # Check if item exists if 95 in scores: print("✅ Perfect score achieved!") if 100 in scores: print("✅ Master score achieved!") else: print("❌ Master score not yet achieved") # Count occurrences scores_with_repeats = [85, 92, 85, 95, 85, 88] print(f"\nScore 85 appears {scores_with_repeats.count(85)} times") ``` ::: {.tip-box} **💡 Common List Methods**: - `list.append(item)` - Add item to end - `list.remove(item)` - Remove first occurrence - `list.pop()` - Remove and return last item - `list.insert(index, item)` - Insert at position - `list.sort()` - Sort the list in place - `list.reverse()` - Reverse the list in place - `len(list)` - Get number of items ::: ## 🧩 Puzzle Time! What will this code produce? Think through it, then run: ```{pyodide-python} # The Mystery List mystery = [10, 20, 30, 40, 50] mystery.append(60) mystery.insert(0, 5) mystery.remove(30) mystery.pop() print(mystery) # Can you trace through each operation? # What's in the final list? ``` ::: {.solution-box} **🔑 Solution Explained**: The final list is: `[5, 10, 20, 40, 50]` **Step-by-step trace**: 1. **Start**: `[10, 20, 30, 40, 50]` 2. **After `append(60)`**: `[10, 20, 30, 40, 50, 60]` - Adds 60 to the end 3. **After `insert(0, 5)`**: `[5, 10, 20, 30, 40, 50, 60]` - Inserts 5 at position 0 (beginning) 4. **After `remove(30)`**: `[5, 10, 20, 40, 50, 60]` - Removes the first occurrence of 30 5. **After `pop()`**: `[5, 10, 20, 40, 50]` - Removes the last item (60) **Key insight**: Each method modifies the list in place. The order of operations matters! ::: ## 🎮 Bonus: Slicing Lists You can extract portions of a list using slicing: ```{pyodide-python} # List slicing items = ["helmet", "armor", "sword", "shield", "boots", "gloves"] print("Full inventory:", items) print() # Slicing: list[start:end] (end is exclusive!) print("First 3 items:", items[0:3]) # or items[:3] print("Last 3 items:", items[3:6]) # or items[3:] print("Middle items:", items[2:4]) print() # Advanced slicing print("Every other item:", items[::2]) print("Reverse order:", items[::-1]) print() # Copying a list inventory_copy = items[:] # or items.copy() inventory_copy.append("ring") print("Original:", items) print("Copy:", inventory_copy) # Notice the original didn't change! ``` ## 🎯 Key Takeaways ::: {.quest-complete} ### ✨ Quest 5 Complete! ✨ You've learned: ✅ Lists store multiple items in order ✅ Lists are indexed starting from 0 ✅ Use methods like append(), remove(), pop(), insert() ✅ Access items with bracket notation: `list[index]` ✅ Lists can be sliced, sorted, and reversed ✅ Use `len()`, `max()`, `min()`, `sum()` for analysis **Next Quest**: Ready to create reusable code? Try [Quest 6: Functions](06-functions.qmd)! ::: ## 🚀 Try This at Home! Create a to-do list manager: ```python # Simple to-do list tasks = ["Learn Python", "Build a game", "Read a book"] print("MY TO-DO LIST") for i, task in enumerate(tasks, 1): print(f"{i}. {task}") # Add new task tasks.append("Practice coding") # Mark a task as done (remove it) completed = tasks.pop(0) print(f"\nCompleted: {completed}") print(f"Remaining: {tasks}") ``` Or make a high score tracker: ```python high_scores = [1500, 1200, 1000, 950, 800] new_score = 1100 high_scores.append(new_score) high_scores.sort(reverse=True) high_scores = high_scores[:5] # Keep only top 5 print("Top 5 High Scores:") for rank, score in enumerate(high_scores, 1): print(f"{rank}. {score} points") ``` --- ::: {.tip-box} **📱 Excellent Progress!** Lists are essential in almost every program. Master them! 📋 :::