On 24/03/17 21:41, boB Stepp wrote: >> I have a question: When creating an instance of GroceryListMaker, you are >> using: >> >> if __name__ == "__main__": >> >> What is that specifically for?
Its a common trick in Python that enables a single file to act as both a module and a program. When a script is imported Python sets its __name__ attribute to the name of the module. When a script is executed directly Python sets its __name__ to __main__. Thus >> if __name__ == "__main__": >> my_shopping_list = GroceryListMaker() >> my_shopping_list.make_shopping_list() >> my_shopping_list.display_shopping_list() Means only execute the three indented lines if running the file directly, do not execute them if the file is being imported. Whereas: >> my_shopping_list = GroceryListMaker() >> my_shopping_list.make_shopping_list() >> my_shopping_list.display_shopping_list() will result in the three lines being executed regardless of whether the file is imported or executed directly. You will see this idiom in many files even when they are not intended to be run directly because it is common to create a tests or a demonstration that will run when executed directly. HTH -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
