In Python, the special variable __name__ is used to determine if a Python script is being run as the main program or as an imported module. When a Python script is executed, the __name__ variable is automatically set to "__main__" if the script is the main program. If the script is imported as a module, the __name__ variable is set to the name of the module.
Example 1: Running a Python Script as the Main Program
# main.py
def main():
print("This is the main function")
if __name__ == "__main__":
main()
In this example, the main() function is defined and the if __name__ == "__main__": statement is used to check if the script is being run as the main program. If it is, the main() function is executed, and the output is:
This is the main function
Example 2: Importing a Python Script as a Module
# main.py
def main():
print("This is the main function")
if __name__ == "__main__":
main()
# import.py
import main
In this example, the main.py script is imported as a module into another Python script called import.py. When the import.py script is executed, the main.py script is imported, but the if __name__ == "__main__": statement is not executed, so the main() function is not executed and there is no output.
Conclusion
The __name__ variable is a powerful and versatile tool in Python that allows you to determine if a script is being run as the main program or as an imported module. This can be useful in a variety of applications and can help you write cleaner, more organized, and more maintainable code.
