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Python Variables and Data Types

In this tutorial, you'll learn about variables and data types in Python. We'll use real-world examples that you can relate to, making it easier to understand these fundamental concepts.

What is a Variable?

Think of a variable as a container or a labeled box where you can store different types of information. Just like how you might label a box "School Supplies" to store your notebooks and pens, in Python, we use variables to store data.

Python
1# Creating variables is like labeling boxes
2student_name = "Maria"
3age = 15
4grade = 9.5
5is_present = True

Common Data Types in Python

1. Strings (text)

Strings are used to store text. Think of your favorite social media platform - when you write a post or message, you're creating a string!

Python
1# Examples of strings
2message = "Hello, World!"
3favorite_food = 'Pizza'
4long_text = """This is a
5multi-line
6text."""
7

8# You can combine (concatenate) strings
9greeting = "Hi, " + student_name
10print(greeting)  # Output: Hi, Maria

2. Numbers

Python has two main types of numbers: integers (whole numbers) and floats (decimal numbers). Think of counting money - whole dollars would be integers, while cents would make it a float.

Python
1# Integers (whole numbers)
2age = 15
3number_of_siblings = 2
4

5# Floats (decimal numbers)
6height = 1.75
7temperature = 98.6
8

9# Basic math operations
10total_cost = 10.99 + 5.99
11print(total_cost)  # Output: 16.98

3. Booleans (True/False)

Booleans are like simple yes/no or on/off switches. Think of your phone's settings - WiFi can be either on (True) or off (False).

Python
1# Boolean examples
2is_sunny = True
3is_raining = False
4

5# Common comparisons that result in booleans
6is_teenager = age >= 13 and age <= 19
7print(is_teenager)  # Output: True
8

9has_passed = grade >= 7.0
10print(has_passed)  # Output: True

Variable Naming Rules

When naming variables in Python, follow these simple rules:

  • Start with a letter or underscore
  • Can contain letters, numbers, and underscores
  • Cannot use Python keywords (like 'if', 'for', 'while')
  • Case-sensitive (age and Age are different variables)
Python
1# Good variable names
2user_name = "John"
3age_in_years = 25
4total_score = 95.5
5

6# Bad variable names (don't do this!)
71st_place = "Gold"  # Can't start with a number
8my-name = "Alex"    # Can't use hyphens
9class = "Math"      # Can't use Python keywords

Practice Exercise

Let's create a simple program that stores information about a student:

Python
1# Create variables for a student profile
2student_name = "Alex"
3student_age = 16
4student_grade = 9.8
5is_enrolled = True
6

7# Print student information
8print("Student Profile:")
9print("Name:", student_name)
10print("Age:", student_age)
11print("Grade:", student_grade)
12print("Currently Enrolled:", is_enrolled)
13

14# Calculate if the student has honors (grade > 9.5)
15has_honors = student_grade > 9.5
16print("Honors Student:", has_honors)

🎯 Try it yourself!

Create your own variables to store information about:

  • Your favorite movie (title, year, rating)
  • A recipe (name, cooking time, difficulty level)
  • A game score (player name, points, is_high_score)

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