Python - Variable Names Explained with Examples - Python Tutorial

Python Programming

Python Variable Names

When writing Python code, variable names are the foundation of clean, readable, and maintainable scripts. Choosing the right variable names is more than just a good habit—it's essential for professional development and debugging.

In this article, we'll cover:

What are variables in Python?
Rules for naming variables
Best practices for variable naming
Valid and invalid variable name examples
Common naming conventions in Python

What Is a Variable in Python?

A variable in Python is a name that refers to a value stored in memory. You can think of it as a label attached to a piece of data.

message = "Hello, Python!"
print(message)

Here, message is a variable that stores the string "Hello, Python!".

Rules for Naming Variables in Python

Python has specific rules when it comes to naming variables:

Variable names must start with a letter (a-z, A-Z) or an underscore _.
Subsequent characters can include letters, digits (0-9), or underscores.
Variable names are case-sensitive (name and Name are different).
Cannot use Python keywords (e.g., class, if, else, True, etc.).

✅ Valid variable names:

username = "john_doe"
user1 = "Jane"
_user = "Hidden"
first_name = "Alice"

❌ Invalid variable names:

1user = "Invalid"      # Starts with a digit
user-name = "Error"    # Hyphen is not allowed
class = "Python"       # 'class' is a reserved keyword

✅ Best Practices for Naming Variables

Follow these best practices to make your code clean and professional:

1. Use Descriptive Names

Avoid single letters or vague names.

# Bad
x = 100

# Good
user_score = 100

2. Use Snake Case for Variable Names

Python recommends using snake_case (lowercase words separated by underscores).

total_price = 49.99

3. Avoid Reserved Keywords

Don’t name variables after Python’s built-in functions or keywords.

# Bad
list = [1, 2, 3]  # Overwrites the built-in list function

# Good
number_list = [1, 2, 3]

Common Python Naming Conventions

Style	Usage Example	Description
snake_case	`user_email`	Standard for variables and functions
camelCase	`userEmail`	Not common in Python (used in JavaScript)
UPPER_CASE	`MAX_RETRIES`	For constants
_underscore	`_private_var`	Indicates a variable is meant for internal use
dunder	`__init__`	Special methods in Python (double underscore)

Variable Naming Examples in Action

Here’s a simple example showing good variable naming:

first_name = "John"
last_name = "Doe"
full_name = first_name + " " + last_name

print("Full Name:", full_name)

Output:

Full Name: John Doe

Conclusion

Choosing the right Python variable names improves code readability and reduces errors. Always follow naming rules and best practices to write Pythonic code.

✨ Key Takeaways:

Variable names must start with a letter or underscore.
Use meaningful, descriptive names in snake_case.
Avoid Python keywords and built-in names.
Follow PEP 8 naming conventions.

By following these guidelines, you'll write cleaner and more maintainable Python code that others (and future you) will thank you for!

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