> I have tried to follow the tutorial I found here: > > Python 2.7 Tutorial > http://www.youtube.com/watch?v=uh6AdDX7K7U > > This is what I have done so far: > > #!/usr/bin/python > > from Tkinter import * > import Tkinter.MessageBox
I figured I might as well, given how I recently had to learn about this, give you a heads up on imports. The format "from module import * " is not a very good idea: it makes your code harder to read (as the reader has to inspect each and every barename to check whether it's actually assigned locally OR comes from the deuced *). To quote the Zen of Python; "namespaces are a honking great idea -- let's do more of those!". You can import modules with several different syntaxes: import importable import importable1, importable2, ..., importableN import importable as preferred_name Here importable is usually a module such as collections, but could be a package or module in a package, in which case each part is separated with a dot, for example os.path. The first two syntaxes are the simplest and also the safest because they avoid the possibility of having name conflicts, since they force us to always use fully qualified names. The third syntax allows us to give a name of our choice to the package or module we are importing. Theoretically, this could lead to name clashes, but in practice the "import importable as" syntax is used to avoid them. There are some other import syntaxes: from importable import object as preferred_name from importable import object1, object2, ..., objectN from importable import (object1, object2, ..., objectN) from importable import * In the last syntax, the * means "import everything that is not private", which in practical terms means either that every object in the module is imported except for those whose names begin with a leading underscore, or, if the module has a global __all__ variable that holds a list of names, that all the objects in the __all__ variable are imported. The from importable import * syntax imports all the objects from the module (or all the modules from the package) -- this could be hundreds of names. In the case of from os.path import *, almost 40 names are imported, including "dirname", "exists", and "split", any of which might be names we would prefer to use for our own variables or functions. For example, if we write from os.path import dirname we can conveniently call dirname() without qualification. But if further on in our code we write dirname = "." the object reference dirname will now be bound to the string "." instead of to the dirname() function, so if we try calling dirname() we will get a TypeError exception because dirname now refers to a string, and we can't call strings. However, given that Tkinter is such a huge package to begin with, I'd say that you should continue to use from Tkinter import *, but be aware of what you're doing when you type that, and that there is a certain risk of conflicts. best regards, Robert S. _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
