Organizing Python classes in modules and/or packages

Question

I like the Java convention of having one public class per file, even if there are sometimes good reasons to put more than one public class into a single file. In my case I have alternative implementations of the same interface. But if I would place them into separate files, I'd have redundant names in the import statements (or misleading module names):

import someConverter.SomeConverter 

whereas someConverter would be the file (and module) name and SomeConverter the class name. This looks pretty inelegant to me. To put all alternative classes into one file would lead to a more meaningful import statement:

import converters.SomeConverter 

But I fear that the files become pretty large, if I put all related classes into a single module file. What is the Python best practise here? Is one class per file unusual?

Answer 1

Zach's solution breaks on Python 3. Here is a fixed solution.

A lot of it is personal preference. Using python modules, you do have the option to keep each class in a separate file and still allow for import converters.SomeConverter (or from converters import SomeConverter)

Your file structure could look something like this:

* converters      - __init__.py      - baseconverter.py      - someconverter.py      - otherconverter.py 

and then in your __init__.py file:

from converters.baseconverter import BaseConverter from converters.otherconverter import OtherConverter 

Answer 2

A lot of it is personal preference. Using python modules, you do have the option to keep each class in a separate file and still allow for import converters.SomeConverter (or from converters import SomeConverter)

Your file structure could look something like this:

* converters      - __init__.py      - baseconverter.py      - someconverter.py      - otherconverter.py 

and then in your __init__.py file:

from baseconverter import BaseConverter from otherconverter import OtherConverter