What is the purpose of if __name__ == "__main__": in Python?

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Khushi Singh · Answer

The if __name__ == "__main__": line in Python controls the execution of script code based on direct execution or import usage as a module.
Purpose
A Python file execution triggers the built-in variable __name__ with a specific value. When running a file directly, the built-in __name__ variable receives a value of "__main__". When a script functions as a module through import, then __name__ receives the module name, which excludes the '.py' extension.
The conditional block surrounding selected code blocks gives you a way to optimize runtime execution.
if __name__ == "__main__":
   # Code to execute only if run directly
The code block executes only under conditions where the script runs directly instead of being loaded through other imports.
Why It’s Useful
The practice allows you to import functions, classes, and variables from other scripts without causing extra code execution.The structure enables clean division of testing functions from the main execution code and demonstration examples.Code modules become more easily reusable while their maintenance becomes enhanced.
Example
def greet():
   print("Hello from greet function!")
if __name__ == "__main__":
   greet()
   print("This script is being run directly.")
Running this file leads to displaying both lines; however, importing the file into another program provides access to greet() alone. Other files accessing this module will only receive the greet() function since the print statements remain unavailable for automatic execution. The approach for managing files using import is standard practice in
Python platform development.
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What is the purpose of if name == "main": in Python?

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