Identifiers in Python: Naming Rules & Best Practices
Updated on Mar 07, 2025 | 7 min read | 15.0k views
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Updated on Mar 07, 2025 | 7 min read | 15.0k views
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Python is an object-oriented high-level programming language that has been widely accepted for general-purpose programming. Built by the Python Software Foundation in 1991, it has found its way into industrial-level programming and is currently the #3 most used programming language globally. As per Statista, nearly 48.24% of developers rely on Python to achieve desirable results in data science, making the language one of the most highly desirable data science skills for job seekers, apart from R and SQL.
The internet is flooded with courses that teach Python within months. Due to the rules mentioned above, the rapid growth of internet learning is flooded with courses on Python, which are now available to a broader audience across all age groups.
Like all programming languages, Python too has its attributes and rules that need to be followed when creating software applications. This article will discuss identifiers in Python and explore the rules and best practices for naming identifiers.
Different programming elements need to be identified and named uniquely to differentiate them from others of the same kind. These are referred to as Identifiers. The user defines these names according to their choice and requirements, including names for classes, functions, variables, methods, and more.
In Python, identifiers follow similar principles but also adhere to specific naming conventions unique to the language. Understanding what are identifiers in Python is essential for writing clean and efficient code. Python identifiers must begin with a letter (A-Z or a-z) or an underscore (_) and can be followed by letters, digits (0-9), or underscores. However, they cannot be Python keywords or contain special characters like @, #, or $.
Also, identifier names cannot be the same as keywords.
Reserved words in Python which cannot be used as an identifier like function names or variable names are known as keywords. They are helpful in the definition of the structure and syntax of Python. As of Python 3.7, there are 33 keywords. This number may increase or decrease over time. Except ‘True’, ‘False’, and ‘None’, all other keywords are found in lowercase and need to be used accordingly, keeping the case sensitivity in mind.
For naming identifiers, Python has a unique set of rules that need to be followed. Here’s taking a look:
Deviation from any of these rules mentioned above may lead to error reports and cause runtime issues in the program:
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Any combination of numbers, letters, and underscores which comply with the mentioned rules are accepted as valid Python identifiers. Some examples are:
Many identifier names that may be valid in other programming languages are invalid in the case of Python. Some examples are:
Python has a function which developers can use to check if an identifier name will be declared valid or not. It is the function identifier().
However, the limitation of this function is that it does not consider reserved keywords for identification.
To overcome this limitation, Python provides another function known as keyword identifier(). This function checks the validity of an identifier name while keeping the keywords in mind.
For example;
print(“xyz”.isidentifier())
print(“88x”.isidentifier())
print(“_”.isidentifier())
print(“while”.isidentifier())
Output:
True
False
True
True (incorrect output)
There is another function str.isidentifier(), that can determine whether an identifier name is valid or not.
Although following Python’s rules is enough for generating unique identifier names which will be declared valid, professionally, users are suggested to follow a certain naming practice. This reduces minute, unforeseen problems and errors while experimenting with different types of identifier names. Even though these errors may seem negligible and might not report syntax errors initially, they can lead to runtime, or logical errors can occur, consequently displaying unwanted results.
(For perspective, errors that occur in the code are known as syntax errors. When the syntax is correct, but the logic is wrong – ultimately leading the program towards a different path – the error is known as a runtime error.)
Here are the best naming practices for Identifiers in Python:
Apart from this Following are the Best Naming Practices for Identifiers in Python
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Also, Read Identity Operator in Python
Python is one of the most widely used programming languages of the current decade. Its ease of use and ability to simplify complex coding tasks give it an edge over other contemporary languages.
Understanding identifiers in Python is essential for writing efficient and error-free code. Since identifiers are user-defined names, they must be unique within a program. As long as the naming rules are followed, these identifiers can be used without issues. However, to enhance readability and maintainability, it is advisable to follow universally accepted naming conventions.
We hope this article helped you understand what are identifiers in Python and how to use them effectively. Happy coding!
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