Variables & Data Types Review

Back to basics — but faster and deeper

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⏳ Loading Python... (first load takes ~10 seconds)

📖 Concept Recap

Python has four main data types you’ll use constantly:

int — whole numbers: 42, -7, 0
float — decimal numbers: 3.14, -0.5, 2.0
str — text: "hello", 'Python'
bool — True or False (capital T/F, no quotes)

Variables are just labels that point to values. Type matters — Python treats "5" and 5 very differently. Use type() to check, and int(), float(), str() to convert.

👀 Worked Example

Study this code carefully before diving into the exercises:

# Data types in action name = "Layla" age = 22 gpa = 3.85 enrolled = True print(type(name)) # <class 'str'> print(type(age)) # <class 'int'> print(type(gpa)) # <class 'float'> print(type(enrolled)) # <class 'bool'> # Type conversion age_as_text = str(age) print("I am " + age_as_text + " years old") print(f"GPA: {gpa:.1f}") # f-string formatting

✏️ Guided

Exercise 1 — Student Profile Variables

Fill in the blanks to create a complete student profile and print a formatted summary. Replace each ___ with a real value.

# Fill in the blanks!
student_name = "___"      # Your name
student_age = ___         # Your age as an integer
student_major = "___"     # Your major
honor_roll = ___          # True or False

# Print a formatted profile
print(f"Name: {student_name}")
print(f"Age: {student_age}")
print(f"Major: {student_major}")
print(f"Honor Roll: {honor_roll}")
print(f"Type check — age is a: {type(student_age)}")

Output will appear here...

💡 Hint: Strings need quotes. Integers don’t. True and False are capitalized and have no quotes.

💪 Independent

Exercise 2 — Product Inventory

Write code that stores a product name (str), price (float), quantity (int), and whether it’s in stock (bool). Then print:

The total value (price × quantity)
A sentence like: "Product Notebook: $5.99 each, 12 in stock."

# Your code here

Output will appear here...

💡 Hint: Use f"Product {name}: ${price} each, {qty} in stock." to format the sentence.

🔥 Challenge

Exercise 3 — Type Conversion Puzzle

Python’s type conversion can fail in surprising ways. Your tasks:

Try to convert the string "3.14" to an integer directly using int("3.14") — run it and see what happens.
Find the correct two-step method to convert "3.14" to an integer.
Print the result and verify its type is <class 'int'>.

# Hint: int() and float() are your tools
# Step 1 — try this (it will error):
# result = int("3.14")

# Step 2 — find the correct two-step approach:

# Step 3 — print the result and its type:

Output will appear here...

💡 Hint: You can nest function calls: int(float("3.14")). Think about why that works.

🏆 Mini Project

Mini Project — Personal Profile Card Builder

Build a complete personal profile. Store: full name, age, city, major, GPA, year (Freshman/Sophomore/Junior/Senior), and is_full_time (bool). Then print a formatted profile card that looks like this:

============================
        STUDENT PROFILE
============================
Name:    Layla Hassan
Age:     22
City:    Los Angeles
Major:   Data Science
GPA:     3.9
Year:    Junior
Status:  Full-Time
============================

# Build your profile card here!

Output will appear here...

💡 Hint: Use f-strings with alignment: f"{'Name:':<8} {name}" creates neat columns. Or just use spaces manually.

✅ Lab 1 Complete!

You’ve reviewed variables, data types, type conversion, and f-string formatting. These are the building blocks of every Python program you’ll ever write.

Continue to Lab 2: Conditionals & Logic →

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