The statement if __name__ == "__main__": is a common idiom used in Python to allow a module to be run as a standalone program or be imported and used by another module.

When a Python module is run directly as a script, the special variable __name__ is set to "__main__". On the other hand, when a module is imported by another module, __name__ is set to the name of the module.

Therefore, the if __name__ == "__main__": statement allows you to distinguish between these two cases. Anything that you put within this if statement will only be executed if the module is run as a standalone program, and will not be executed if the module is imported by another module.

Here's an example:

# module.py



def my_function():

    print("Hello, world!")



if __name__ == "__main__":

    my_function()

If you run this module directly (python module.py), the output will be:

Output:
Hello, world!

However, if you import this module into another module, the function my_function() will not be executed automatically. You can call it explicitly from the other module if you want to use it.