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What is Identifier in Python?

What is Identifier in Python?
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In this blog, we’ll explore the role of identifiers as labels for elements in Python code. We’ll delve into the rules governing their creation, providing examples, highlighting the advantages they offer, and concluding by emphasizing their importance in coding practices.

Table of Contents:

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What is Identifier in Python? 

An Identifier in Python is a name used to identify variables, functions, classes, modules, or any other user-defined objects within a program. Identifiers serve as labels or tags for these elements, allowing you to reference and manipulate them in your code. In Python, identifiers are essential because they improve the maintainability, readability, and logic of your code.

You may improve the readability of your code for both yourself and any potential coworkers by giving identifiers names that are relevant and descriptive. The likelihood of mistakes or misunderstandings when examining or changing the code is decreased by this method, which also promotes clarity. 

Identifiers are governed by a set of rules and conventions in Python. They must begin with a letter or an underscore and then contain either a letter, an underscore, or a number. Python also recognizes uppercase and lowercase letters differently due to its case sensitivity. As a best practice, variable and function names should be written in lowercase, whereas class names should be written using the “CamelCase” style.

Furthermore, Python’s adherence to the PEP 8 style guide encourages uniformity in code layout and naming conventions, facilitating developers’ easy collaboration. Essentially, identifiers serve as signposts in your Python code, leading you and other programmers through the program’s architecture and functionality and producing more understandable, efficient, and maintainable code.

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Rules for Writing an Identifier in Python 

Python’s identifier naming conventions are essential for the readability and functionality of the code. Additionally, these regulations help preserve uniformity in programming methods by preventing conflicts with reserved keywords. The guidelines for naming identifiers in Python are as follows:

  1. Character Composition: Characters, numbers, and underscores make up identifiers. Lowercase letters (a–z), uppercase letters (A–Z), numbers (0–9), and underscores (_) are all part of the acceptable character set.
  2. Cannot Begin with a Digit: No identifier can begin with a number. A syntax error occurs if an identifier begins with a number.
  3. Avoid Keywords: Python has reserved keywords that serve specific purposes in the language. Identifiers cannot be named after these keywords, as they have special meanings and cannot be used as variable names.
  4. Special Symbols: Identifiers cannot contain special symbols like !, @, #, $,%, etc. There can only be letters, numbers, and underscores.
  5. Cannot Consist Only of Digits: An identifier must have at least one character (a letter or an underscore) in addition to numerals. It cannot only be made up of numbers.
  6. No Length Restrictions: Identifiers are not subject to any set length restrictions. Although they can be any length, it’s a good idea to keep them brief and relevant.
  7. Case-Sensitive: Python is case-sensitive, which means that different identifiers (such as “myVar” and “myvar”) are treated differently. To avoid confusion, be consistent in your usage.

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Examples of Identifiers in Python 

Valid identifiers follow the rules and conventions mentioned earlier, while invalid identifiers violate one or more of those rules. Here’s a table with some examples of valid and invalid Python identifiers:

Valid IdentifiersInvalid Identifiers
my_variable  123variable  
total_amount @special_identifier
_private_var    if_keyword 
max_value_1space identifier
ClassExample break   

Valid Python Identifier

valid_identifier = "Hello, Python!"


Hello, Python!

Invalid Python Identifier

123invalid = "This won't work"


SyntaxError: cannot assign to literal

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Advantages of Identifiers in Python

In Python, Identifiers are used to give names to variables, functions, classes, modules, and other user-defined objects. Here are some advantages that are described further:

Readability and Understanding: Code is more readable and self-explanatory when identifiers are descriptive and meaningful. They make it simpler for developers to comprehend and maintain the code by explaining the function and use of variables and functions.

Maintainability: Carefully chosen identifiers make it easier to maintain code. When identifiers are named after their intended use, it is simpler to find and edit particular sections of the code without making mistakes.

Code Documentation: Clear identifiers are an efficient way to document your code. They act as inline comments, eliminating the need for separate comments to describe the function or variable’s purpose.

Collaboration: Collaboration is facilitated by uniform naming conventions and useful identifiers while working on projects with several developers. The codebase’s functions and structure are easily understood by team members.

Error Avoidance: Correctly named identifiers lessen the possibility of naming conflicts and mistakes. By giving things descriptive names, you may avoid reusing names or accidentally overwriting variables.

Debugging: Identifiers that accurately reflect the code’s intent can help with debugging. Meaningful identifiers make it easier for developers to locate the problem’s origin when a problem occurs.

Documentation Generation: Some tools and systems for documenting can produce documentation from code automatically, and the quality of the documentation so produced is improved by the use of meaningful identifiers.

Best Practices Compliant: By following accepted name conventions and identifier rules, such as Python’s PEP 8 style guide, you may be sure that your code complies with best practices and industry standards.

Reusability of Code: Meaningful identifiers promote the reusability of code. You are more likely to reuse functions, classes, and modules in other portions of your project or in other projects when your code is well-structured and easy to understand.

Enhanced Search and Navigation: Using integrated development environments (IDEs) or text editors, it is simpler to search for and navigate to specific elements when your codebase contains descriptive identifiers.

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In Python, well-considered identifiers are important for code clarity, maintenance, and teamwork. They improve code readability, cut down on errors, and encourage productive developer collaboration. Clear identifiers speed up software development for business applications while maintaining maintainability and readability. Identifiers are more than just names; they are the foundation upon which the future of Python coding is built. So, keep innovating and watch your Python projects thrive in the dynamic world of programming.

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About the Author

Senior Consultant Analytics & Data Science

Presenting Sahil Mattoo, a Senior Consultant Analytics & Data Science at Eli Lilly and Company is an accomplished professional with 14 years of experience across data science, analytics, and technical leadership domains, demonstrates a remarkable ability to drive business insights. Sahil holds a Post Graduate Program in Business Analytics and Business Intelligence from Great Lakes Institute of Management.