Identifiers:

These are the names that are used to identify the variables, functions, classes, modules or other objects. Whenever we define something in python and give it a name then we call it as an identifier.

Identifier Rules:

1. Identifier cannot be a keyword.
2. It is case sensitive.
3. It may contain a single alphabet or a word or alpha-numeric.
4. It cannot start with a digit, but can have a digit in the middle or last .
5. It cannot have any other special character apart from ‘_’(underscore).
6. It cannot start with a space or have a space in the middle.
7. It can be of any length, but should be meaningful and readable.

Best Practices of Naming Identifiers

• Use snake_case for variables and functions:

Eg: 

student_name, calculate_total, average_score

• Use PascalCase for class names:

Eg: 

class StudentDetails:

pass

• Use UPPERCASE for constants:

Eg:

PI = 3.141

• Choose meaningful names:

Eg: 

x = 10 # vague
marks_obtained = 10 # better