Thanks Walter; I believe I understand the reasoning behind it, though not all of the mechanics, but for now, your answer is more than sufficient.
-Alex On Thu, Jun 14, 2012 at 4:10 PM, Walter Prins <wpr...@gmail.com> wrote: > Hi Alex, > > On 14 June 2012 23:18, Alexander Quest <alexxqu...@gmail.com> wrote: > > if __name__ == '__main__': > > main() > > > > This calls the main function, but I don't understand what the 'if' > statement > > is doing here. In the simple programs that I've seen this so far, there > is > > no variable called "_name_", and even if there was, why is it comparing > it > > to "_main_"? Why can't the main function just be called by typing main()- > > why do we need this if statement to precede it? Thanks. > > In short, consider the implications of the fact that your file, apart > from being a program that can run standalone, might also be a Python > module that might be used in another program. Oftentimes you want to > write your Python code in such a way that when the module is run > directly you want it to do something useful (such as run a main() > function, e.g. maybe run some unit/self-tests or whatever), while when > you import it for use in another program/module then you probably > rather do *not* want it to run as if it is itself the "main program". > So, in order to differentiate the 2 cases, there exists the above > Python idiom. So, when a module is directly run as the "main > program", then the name of the module being run, which is reflected by > the variable __name__, made available by the Python interpreter, will > be equal to "__main__", while when it's imported it will be equal to > the module name. This allows your module to know when it's running > whether it's running as the main program or just running because it's > been imported by another module. > > Does that answer your question? > > Walter >
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