I have a module whose purpose is to define a class called “nib”. (and a few related classes too.) How should I call the module itself? “nib”? “nibmodule”? Anything else?

Just nib. Name the class Nib, with a capital N. For more on naming conventions and other style advice, see PEP 8, the Python style guide.

I would call it nib.py. And I would also name the class Nib.

In a larger python project I’m working on, we have lots of modules defining basically one important class. Classes are named beginning with a capital letter. The modules are named like the class in lowercase. This leads to imports like the following:

from nib import Nib
from foo import Foo
from spam.eggs import Eggs, FriedEggs

It’s a bit like emulating the Java way. One class per file. But with the added flexibility, that you can allways add another class to a single file if it makes sense.

I know my solution is not very popular from the pythonic point of view, but I prefer to use the Java approach of one module->one class, with the module named as the class. I do understand the reason behind the python style, but I am not too fond of having a very large file containing a lot of classes. I find it difficult to browse, despite folding.

Another reason is version control: having a large file means that your commits tend to concentrate on that file. This can potentially lead to a higher quantity of conflicts to be resolved. You also loose the additional log information that your commit modifies specific files (therefore involving specific classes). Instead you see a modification to the module file, with only the commit comment to understand what modification has been done.

Summing up, if you prefer the python philosophy, go for the suggestions of the other posts. If you instead prefer the java-like philosophy, create a Nib.py containing class Nib.

nib is fine. If in doubt, refer to the Python style guide.

From PEP 8:

Package and Module Names Modules should have short, all-lowercase names. Underscores can be used in the module name if it improves readability. Python packages should also have short, all-lowercase names, although the use of underscores is discouraged.

Since module names are mapped to file names, and some file systems are case insensitive and truncate long names, it is important that module names be chosen to be fairly short — this won’t be a problem on Unix, but it may be a problem when the code is transported to older Mac or Windows versions, or DOS.

When an extension module written in C or C++ has an accompanying Python module that provides a higher level (e.g. more object oriented) interface, the C/C++ module has a leading underscore (e.g. _socket).

From PEP-8: Package and Module Names:

Modules should have short, all-lowercase names. Underscores can be used in the module name if it improves readability.

Python packages should also have short, all-lowercase names, although the use of underscores is discouraged.

When an extension module written in C or C++ has an accompanying Python module that provides a higher level (e.g. more object oriented) interface, the C/C++ module has a leading underscore (e.g. _socket).

foo module in python would be the equivalent to a Foo class file in Java

or

foobar module in python would be the equivalent to a FooBar class file in Java