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Alan Gauld Author of the Learn To Program website http://www.alan-g.me.uk/ >________________________________ > From: #PATHANGI JANARDHANAN JATINSHRAVAN# <jatinshr...@e.ntu.edu.sg> >To: Alan Gauld <alan.ga...@btinternet.com> >Sent: Monday, 22 July 2013, 17:14 >Subject: RE: [Tutor] Cannot understand what this means > > >Hi >I have doubts only on the arguments part. > >OK, But what about them? Do you understand what command line arguments are? > def main(): > >> # This command-line parsing code is provided. >> # Make a list of command line arguments, omitting the [0] element >> # which is the script itself. >> args = sys.argv[1:] This fetches the command line arguments missing the first which is the program name. Do you understand slicing? Do you understand how sys.argv works - its similar to the argc, argv mechanism of C++ which you've maybe seen before. >> if not args: >> print 'usage: [--summaryfile] file [file ...]' >> sys.exit(1) The logic here says that if args is empty then print the message and exit >> # Notice the summary flag and remove it from args if it is present. >> summary = False >> if args[0] == '--summaryfile': >> summary = True >> del args[0] I have no idea why this is here but for whatever reason he is setting the summary flag to True if the first argument was --summaryfile Now, is there anything else you don't understand? The more specific you make your questions the better we can answer them. Alan G. _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
