📖 📓 Python Variables

📖 📓 Python Variables#

🥨 Introduction to Variables: “Yo, What’s a Variable?”#

In Philly terms, a variable is like a cheesesteak order: it holds something specific and meaningful (like “Whiz wit” means “Cheesesteak with Cheese Whiz and onions”).

Definition:#

A variable is a named container that stores data, like a string, number, or list.

Why use variables?#

  • To organize your code.

  • To make your code reusable.

  • To make your data easy to reference and modify.

# Example: Philly Cheesesteak Orders
order_1 = "Whiz wit"
order_2 = "American witout"
print(order_1, "and", order_2)

Whiz wit and American witout

🏙️ Variable Naming Rules: “Keep it Respectable Like the Liberty Bell”#

Rules for Naming Variables:#

  1. Must start with a letter or underscore (_).

  2. Can include letters, numbers, and underscores, but no spaces or special characters.

  3. Are case-sensitive (hoagie and Hoagie are different).

  4. Use descriptive names (don’t be like a lost tourist at the Italian Market).

# Good Variable Name
hoagie_order = "Italian with extra peppers"

# Bad Variable Name
x = "What kind of order is this?"

⚾ Variable Types: “From Soft Pretzels to Phillies Home Runs”#

In Python, variables can hold different data types. Here’s a quick rundown:

Common Variable Types:#

  1. Integer (int): Whole numbers, like the number of pretzels in your bag.

  2. Float (float): Numbers with decimals, like the price of a cheesesteak.

  3. String (str): Text, like the names of Philly landmarks.

  4. Boolean (bool): True/False, like “Is Wawa the best? True.”

  5. List (list): A collection, like all your favorite toppings.

# Examples
pretzel_count = 5  # Integer
cheesesteak_price = 12.99  # Float
landmark = "Liberty Bell"  # String
is_wawa_best = True  # Boolean
favorite_toppings = ["onions", "peppers", "mushrooms"]  # List

🚊 Assigning Variables: “Catch the SEPTA of Python Logic”#

You can assign values to variables using the = operator. It’s like deciding your subway route: Broad Street Line or Market-Frankford Line?

# Broad Street Line Cheesesteak
broad_st_line = "Pat's"

# Market-Frankford Line Cheesesteak
market_frankford_line = "Geno's"

🛶 Variable Reassignment: “Change It Up Like the Schuylkill River Tide”#

Variables can change their value during the program.

favorite_sport = "Baseball"  # Phillies!
print("Favorite sport:", favorite_sport)

# Changing the value
favorite_sport = "Football"  # Eagles!
print("Updated favorite sport:", favorite_sport)

Favorite sport: Baseball
Updated favorite sport: Football

🍕 Multi-Variable Assignment: “Jawn Everything at Once”#

In Philly, “jawn” means anything and everything. Python lets you assign multiple variables at once, like grabbing everything you need for a South Philly tailgate.

# Assigning multiple variables at once
hoagie, pretzel, soda = "Italian", "Soft Pretzel", "Birch Beer"
print(hoagie, pretzel, soda)

Italian Soft Pretzel Birch Beer

🏆 Constants: “Always True Like Rocky Balboa”#

Constants are variables that don’t change (by convention, written in all caps).

# Example: Philly's Famous Landmark
CITY = "Philadelphia"
BEST_FOOD = "Cheesesteak"

🛠️ Variable Type Conversion: “Switch It Up Like a Philly Foodie”#

Sometimes, you need to convert variables to a different type.

# Example: Pretzel Math
pretzel_price = "2.50"  # String
total_price = float(pretzel_price) * 3  # Convert to float and calculate
print("Total price for 3 pretzels: $", total_price)

Total price for 3 pretzels: $ 7.5

🎨 Fun Philly Example: Build Your Cheesesteak#

Here’s a fun example where you build a cheesesteak order using variables:

# Build your Philly Cheesesteak
bread = "Amoroso roll"
meat = "ribeye steak"
cheese = "Cheez Whiz"
toppings = ["fried onions", "mushrooms"]

# Display the order
print("Your cheesesteak order:")
print(f"Base: {bread}, {meat}, with {cheese} and toppings: {', '.join(toppings)}")

Your cheesesteak order:
Base: Amoroso roll, ribeye steak, with Cheez Whiz and toppings: fried onions, mushrooms