The use of Python __name__ and __main__

Use of __name__ and __main__

#hello. py
Def SayHello ():
    str= "Hello"
    Print (str);

if __name__ = = "__main__":
    Print (' This is main of module ' hello.py ')
    SayHello ()

This calls itself to execute all, the following is the execution result, if __name__ = = "__main__" is as a test, call the top-level program code to do the internal unit test. __NAME__ is actually the file itself, __main__ as the main function entrance.

This is main of the module "hello.py"

Hello

If this hello.py is called by another. py file, only the SayHello () function will be executed, and the print syntax will not be executed. This time the __name__ is actually modul (function SayHello ()) itself, which is called Hello.sayhello ()
>>> Import Hello
>>> hello.__name__
' Hello '
>>>

The use of Python __name__ and __main__