Understanding Python’s __name__ == '__main__': The Gateway to Script and Module 🧩📜

Introduction

If you’ve looked at Python scripts, you might have come across this line:

But what does it really mean? This blog demystifies this construct and explains its importance in distinguishing between script and module usage in Python.

The Role of __name__

In Python, every module has a built-in attribute called __name__. When a module is run directly, __name__ is set to "__main__". However, if the module is imported, __name__ is set to the module’s name.

Why Use if __name__ == '__main__':?

This construct allows you to:

• Run Code Only When a Script is Executed Directly:

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• Prevent Code from Running on Import: This is particularly useful if your script contains test code or standalone execution logic that shouldn’t run when the module is imported elsewhere.

Practical Example

Let’s say you have a script called calculator.py with a main() function that performs calculations. By wrapping the call to main() in an if __name__ == "__main__": block, the script will only perform calculations when run directly, not when imported as a module.