How to Use the Python Main Function

**How to Use the Python Main Function**

The Python main function is the conventional entry point for a script: you define a function (typically named main) that holds your program logic and call it only when the file is run directly, not when it is imported as a module. Python does not call main() automatically; the pattern if __name__ == "__main__": is what lets you separate “run as script” from “import as module.” When the file is executed directly, the interpreter sets the special __name__ variable to "__main__", so the block under that condition runs and can call main(). When the file is imported, __name__ is set to the module name, so that block is skipped and your module can be reused without side effects. This article shows how to define and use the Python main function, how CPython assigns __name__, how to make packages runnable with __main__.py, how to integrate argparse, and how to structure scripts for testability and correct exit codes. Key Takeaways The Python main function is not special to the interpreter; you define it yourself and call it from a if __name__ == "__main__": block so it runs only when the file is executed directly...

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