hello_python.py

#!/usr/bin/env python3
"""
🐍 Session 19: Python Basics & Comparison
CoderDojo - Learning Python alongside C#!

This file contains examples of Python basics.
Run it with: python3 hello_python.py
"""

# ============================================================
# 📌 SECTION 1: PRINT STATEMENTS
# The simplest Python program - just say hello!
# ============================================================

print("=" * 50)
print("🐍 Welcome to Python!")
print("=" * 50)

# In C#, you would write: Console.WriteLine("Hello!");
# In Python, it's just:
print("Hello, World!")
print("Python is fun!")
print()  # Empty line


# ============================================================
# 📌 SECTION 2: VARIABLES
# No type declarations needed - Python figures it out!
# ============================================================

print("📦 VARIABLES")
print("-" * 30)

# String variable (text)
name = "Alex"
print(f"Name: {name}")

# Integer variable (whole number)
age = 14
print(f"Age: {age}")

# Float variable (decimal number)
height = 5.6
print(f"Height: {height} feet")

# Boolean variable (True/False)
is_student = True
print(f"Is a student: {is_student}")

# Python allows changing variable types!
my_variable = 10
print(f"my_variable is a number: {my_variable}")
my_variable = "now I'm text!"
print(f"my_variable is now text: {my_variable}")
print()


# ============================================================
# 📌 SECTION 3: GETTING USER INPUT
# Use input() to ask the user for information
# ============================================================

print("🎤 USER INPUT")
print("-" * 30)

# Uncomment these lines to try interactive input:
# user_name = input("What's your name? ")
# print(f"Hello, {user_name}! Nice to meet you!")
#
# user_age = int(input("How old are you? "))
# print(f"Next year you'll be {user_age + 1}!")

# For this demo, we'll use preset values:
user_name = "CoderDojo Student"
user_age = 12
print(f"Hello, {user_name}! You are {user_age} years old.")
print()


# ============================================================
# 📌 SECTION 4: IF STATEMENTS (CONDITIONALS)
# Make decisions in your code!
# ============================================================

print("🔀 IF STATEMENTS")
print("-" * 30)

score = 85

# Notice: no parentheses around condition, use colon at end!
if score >= 90:
    print("Grade: A 🌟")
elif score >= 80:
    print("Grade: B 👍")
elif score >= 70:
    print("Grade: C 😊")
elif score >= 60:
    print("Grade: D 😐")
else:
    print("Grade: F 😢")

# Checking multiple conditions
temperature = 72
is_sunny = True

if temperature > 70 and is_sunny:
    print("Perfect day for the park! ☀️")
elif temperature > 70:
    print("Warm but cloudy 🌥️")
else:
    print("Maybe stay inside 🏠")
print()


# ============================================================
# 📌 SECTION 5: LOOPS
# Repeat code multiple times!
# ============================================================

print("🔄 LOOPS")
print("-" * 30)

# For loop with range
print("Counting to 5:")
for i in range(1, 6):
    print(f"  {i}")

# For loop with a list
print("\nFavorite fruits:")
fruits = ["apple", "banana", "cherry", "dragon fruit"]
for fruit in fruits:
    print(f"  🍎 {fruit}")

# While loop
print("\nCountdown:")
countdown = 5
while countdown > 0:
    print(f"  {countdown}...")
    countdown -= 1
print("  🚀 Blastoff!")
print()


# ============================================================
# 📌 SECTION 6: LISTS
# Store multiple items in one variable!
# ============================================================

print("📋 LISTS")
print("-" * 30)

# Creating a list
colors = ["red", "green", "blue"]
print(f"Colors: {colors}")

# Accessing items (indexing starts at 0!)
print(f"First color: {colors[0]}")
print(f"Last color: {colors[-1]}")  # -1 means last item!

# Adding items
colors.append("yellow")
print(f"After adding yellow: {colors}")

# Removing items
colors.remove("green")
print(f"After removing green: {colors}")

# List slicing (getting parts of a list)
numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
print(f"\nNumbers: {numbers}")
print(f"First 3: {numbers[:3]}")
print(f"Last 3: {numbers[-3:]}")
print(f"Middle (3-7): {numbers[3:7]}")
print(f"Every other: {numbers[::2]}")
print()


# ============================================================
# 📌 SECTION 7: FUNCTIONS
# Reusable blocks of code!
# ============================================================

print("🔧 FUNCTIONS")
print("-" * 30)


# Simple function
def say_hello():
    """A function that says hello."""
    print("Hello from a function! 👋")


say_hello()


# Function with parameter
def greet(name):
    """Greet someone by name."""
    print(f"Hello, {name}! Welcome to Python!")


greet("Ninja Coder")


# Function with return value
def add(a, b):
    """Add two numbers and return the result."""
    return a + b


result = add(5, 3)
print(f"5 + 3 = {result}")


# Function with default parameter
def greet_with_emoji(name, emoji="😊"):
    """Greet someone with a custom emoji."""
    print(f"Hello, {name}! {emoji}")


greet_with_emoji("Alex")
greet_with_emoji("Sam", "🎉")


# Function that works with lists
def calculate_average(numbers):
    """Calculate the average of a list of numbers."""
    if len(numbers) == 0:
        return 0
    return sum(numbers) / len(numbers)


grades = [90, 85, 92, 88, 95]
avg = calculate_average(grades)
print(f"Average grade: {avg}")
print()


# ============================================================
# 📌 SECTION 8: DICTIONARIES
# Key-value pairs - like a real dictionary!
# ============================================================

print("📖 DICTIONARIES")
print("-" * 30)

# Creating a dictionary
student = {
    "name": "Alex",
    "age": 14,
    "grade": 8,
    "favorite_subject": "Computer Science"
}

# Accessing values
print(f"Name: {student['name']}")
print(f"Age: {student['age']}")

# Adding/updating values
student["email"] = "alex@school.com"
student["age"] = 15  # Happy birthday!

# Looping through a dictionary
print("\nAll student info:")
for key, value in student.items():
    print(f"  {key}: {value}")

# Check if key exists
if "name" in student:
    print(f"\nFound student: {student['name']}")
print()


# ============================================================
# 📌 SECTION 9: CLASSES
# Create your own data types!
# ============================================================

print("🏗️ CLASSES")
print("-" * 30)


class Pet:
    """A class representing a pet."""

    def __init__(self, name, species, age):
        """Initialize a new pet with name, species, and age."""
        self.name = name
        self.species = species
        self.age = age
        self.tricks = []

    def speak(self):
        """Make the pet speak based on its species."""
        if self.species == "dog":
            print(f"{self.name} says: Woof! 🐕")
        elif self.species == "cat":
            print(f"{self.name} says: Meow! 🐱")
        elif self.species == "bird":
            print(f"{self.name} says: Tweet! 🐦")
        else:
            print(f"{self.name} says: ...? 🤔")

    def learn_trick(self, trick):
        """Teach the pet a new trick."""
        self.tricks.append(trick)
        print(f"{self.name} learned '{trick}'! 🎉")

    def show_tricks(self):
        """Display all tricks the pet knows."""
        if not self.tricks:
            print(f"{self.name} doesn't know any tricks yet!")
        else:
            print(f"{self.name}'s tricks: {', '.join(self.tricks)}")

    def get_info(self):
        """Return a string with pet information."""
        return f"{self.name} is a {self.age}-year-old {self.species}"


# Creating objects from the class
buddy = Pet("Buddy", "dog", 3)
whiskers = Pet("Whiskers", "cat", 5)

# Using object methods
print(buddy.get_info())
buddy.speak()
buddy.learn_trick("sit")
buddy.learn_trick("roll over")
buddy.show_tricks()

print()
print(whiskers.get_info())
whiskers.speak()
print()


# ============================================================
# 📌 SECTION 10: PUTTING IT ALL TOGETHER
# A mini-project combining everything!
# ============================================================

print("🎮 MINI PROJECT: Book Collection")
print("-" * 30)


class Book:
    """A class representing a book."""

    def __init__(self, title, author, pages):
        self.title = title
        self.author = author
        self.pages = pages
        self.is_read = False

    def mark_as_read(self):
        """Mark the book as read."""
        self.is_read = True
        print(f"✅ Marked '{self.title}' as read!")

    def display(self):
        """Display book information."""
        status = "📗 Read" if self.is_read else "📕 Unread"
        print(f"  {self.title} by {self.author} ({self.pages} pages) - {status}")


# Create a list of books
library = [
    Book("Harry Potter", "J.K. Rowling", 309),
    Book("The Hobbit", "J.R.R. Tolkien", 310),
    Book("Percy Jackson", "Rick Riordan", 377),
    Book("Diary of a Wimpy Kid", "Jeff Kinney", 217)
]

# Mark some as read
library[0].mark_as_read()
library[2].mark_as_read()

# Display all books
print("\n📚 My Book Collection:")
for book in library:
    book.display()

# Calculate total pages
total_pages = sum(book.pages for book in library)
books_read = sum(1 for book in library if book.is_read)

print(f"\n📊 Stats:")
print(f"  Total books: {len(library)}")
print(f"  Books read: {books_read}")
print(f"  Total pages: {total_pages}")
print()


# ============================================================
# 🎉 THE END!
# ============================================================

print("=" * 50)
print("🎉 Congratulations! You've learned Python basics!")
print("=" * 50)
print()
print("📝 What we covered:")
print("  ✅ Print statements")
print("  ✅ Variables")
print("  ✅ User input")
print("  ✅ If statements")
print("  ✅ Loops (for and while)")
print("  ✅ Lists")
print("  ✅ Functions")
print("  ✅ Dictionaries")
print("  ✅ Classes")
print()
print("🐍 Keep practicing and have fun coding!")