Summary  
This chapter explains the rules and conventions for naming variables in Python—covering allowed characters, starting characters, case sensitivity, avoiding reserved keywords, and common naming styles such as snake_case, CamelCase, PascalCase, and uppercase for constants.  

General domain of usage  
Software development

Variables should have descriptive names, such as `is_user_logged_in`, `customer_full_name`, or `total_sales`, to make code more readable and maintainable.

Concise names like `x`, `y`, or `temp` can also be used when necessary. The most important aspect is to follow the rules of naming.

Python will generate an error if you violate variable naming rules, such as starting a variable name with a number, using spaces or special characters, using reserved keywords, or starting with invalid characters.

There is also **different naming conventions** in Python, such as Camel Case, Snake Case (preferred in Python), Pascal Case, and Uppercase with Underscores (commonly used for constants).
```py
# Camel Case 
numberOfActiveUsers = 120

# Snake Case  (preferred in Python)
number_of_active_users = 120

# Pascal Case
NumberOfActiveUsers = 120

# Uppercase with Underscores (for constants)
NUMBER_OF_ACTIVE_USERS = 120
```

Which of these would be valid variable names in Python?

Python is an interpreted high-level general-purpose programming language. Unlike HTML, CSS, and JavaScript, which are primarily used for web development, Python is versatile and can be used in various fields, including software development, data science, and back-end development. In this course, you'll explore the core aspects of Python, and by the end, you'll be crafting your own functions!

Dive into the basics of Python, explore your workspace, and perform simple math operations. Learn how to write readable code using comments and handle both basic and advanced mathematical expressions while displaying your results.

Learn how to store and manage data in Python by working with numbers, text, and variables. Understand how to assign values, follow naming conventions, and explore different data types. Gain hands-on experience with string operations, indexing, slicing, and memory recall techniques to efficiently manipulate text in Python.

Learn how to use comparison and logical operators, work with conditional expressions, and apply membership and type comparisons. Build a strong foundation in writing programs that respond dynamically to different conditions using if/else and if/elif/else structures.

Expand your understanding of data types by learning how to group multiple attributes within a single variable. Explore lists, tuples, and dictionaries to efficiently store and manage structured data, along with essential methods for manipulation and retrieval.

Master the art of writing loops in Python—essential constructs for iterating over lists, tuples, dictionaries, and other data structures. Learn to use while and for loops effectively, explore the range function, and work with nested loops to handle complex iteration patterns.

Explore essential built-in functions in Python and take the next step by creating your own. Learn how to define functions, use conditional logic, modify existing functions, and work with lambda expressions to write efficient, reusable code.

Which of these is a correct way to create a variable?

How do you store the text `"Hello"` in a variable named `greeting`?

Which of these variable names is valid in Python?

What is the correct way to output `"c<>definity"` in the console?

How can you convert the string `"123"` to an integer?

What will happen when the following code is executed?

Python Naming Rules for Variables

Python Naming Rules for Variables