Thanks for the explanation of "main". Some tutorials mention it, some don't. I have written some not trial Python programs and have never had a real need to use that convention, but at least I understand it now.
--Bill On Wed, Dec 1, 2010 at 1:13 PM, Tim Harig <user...@ilthio.net> wrote: > > On Wed, Dec 1, 2010 at 9:08 AM, m b <sn...@hotmail.se> wrote: > >>> > if __name__ == "__main__": > >>> > main() > >> > >> What does this mean? > > It is a Python idiom and a good practice. Strictly speaking it is > unnecessary. Python doesn't recognize any functional initialization > vector other then the start of the file. When Python loads a module, > it executes anything it finds in the module scope (Anything not in the > body of a class or function declaration). Using a main function is just > a convention. You could just place all of your main level code in the > module scope: > > def Subprogram1(): > # code > def Subprogram2(): > # code > def Subprogram3(): > # code > > # main code > > or equivilantly, always execute main(): > > def Subprogram1(): > # code > def Subprogram2(): > # code > def Subprogram3(): > # code > def main(): > # main code > main() > > Both are valid from Python's point of view. > > The 'if __name__ == "__main__":' idiom is used, because it allows the > module to be loaded without running main(). This is useful if you wanted > to use Subprogram2() from another program. Even if you don't forsee using > any of the subprograms (functions to Python), this can be useful when > writing test code as you can import the program as a module to test its > classes or functions separately. > -- > http://mail.python.org/mailman/listinfo/python-list >
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