Python Constants: Improve Your Code's Maintainability
Python Constants: Improve Your Code's Maintainability 관련
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In Python, constants are identifiers for values that don’t change during a program’s execution. Unlike some other languages, Python lacks built-in syntax for constants, treating them as variables that should remain unchanged. You define constants by following a naming convention: use all uppercase letters with underscores separating words. This signals to other developers that these variables should not be reassigned.
By the end of this tutorial, you’ll understand that
- Constants in Python are variables that should remain unchanged throughout execution.
- Python lacks built-in syntax for constants, relying on conventions to signal immutability.
- Defining a constant involves using uppercase letters with underscores for clarity.
- Best practices include defining constants at the top of a file and using descriptive names.
- Built-in constants like
math.pioffer predefined, reliable values, unlike user-defined ones.
To learn the most from this tutorial, you’ll need basic knowledge of Python variables, functions, modules, packages, and namespaces. You’ll also need to know the basics of object-oriented programming in Python.
Conclusion
Now you know what constants are, as well as why and when to use them in your code. You also know that Python doesn’t have strict constants. The Python community uses uppercase letters as a naming convention to communicate that a variable should be used as a constant. This naming convention helps to prevent other developers from changing variables that are meant to be constant.
Constants are everywhere in programming, and Python developers also use them. So, learning to define and use constants in Python is an important skill for you to master.
In this tutorial, you learned how to
- Define Python constants in your code
- Identify and understand some built-in constants
- Improve you code’s readability, reusability, and maintainability with constants
- Use different strategies to organize and manage constants in a real-world project
- Apply various techniques to make your Python constants strictly constant
With this knowledge about what constants are, why they’re important, and when to use them, you’re ready to start improving your code’s readability, maintainability, and reusability immediately. Go ahead and give it a try!
Frequently Asked Questions
Now that you have some experience with Python constants, you can use the questions and answers below to check your understanding and recap what you’ve learned.
These FAQs are related to the most important concepts you’ve covered in this tutorial.
How do you define a constant in Python?
You define a constant in Python by creating a variable with an uppercase name to indicate that its value shouldn’t change. This is a convention, as Python doesn’t enforce immutability.
What naming conventions should you follow for constants in Python?
You should use all uppercase letters with underscores separating words, following the PEP 8 style guide. This helps communicate to other programmers that the variable is intended to be a constant.
What are the best practices for using constants in Python projects?
Use descriptive names and define them at the top of your modules. Keep them in the same module as the related code, or in a dedicated module if they’re used across multiple modules.
How do built-in constants like math.pi differ from user-defined constants?
Built-in constants are predefined and available in Python’s standard library, providing precise values like math.pi for mathematical operations. User-defined constants are created by you to represent values that should remain unchanged.
Does Python have built-in support for constants?
Python doesn’t have built-in support for constants like it does for variables. However, it uses conventions such as uppercase naming to indicate that a variable should be treated as a constant.
Watch Now
This tutorial has a related video course created by the Real Python team. Watch it together with the written tutorial to deepen your understanding: