Question

I am confused how directory name, file name and class name all work together.

This is what I have at the moment

  app.py   database/      client.py      staff.py      order.py 

Inside client.py I have a single class called client, which acts as the database model (MVC). The same with my other files: staff.py has a class called staff, order.py has order.

Then in app.py I do:

  from database import client as model   c = model.client() 

And then I get confused. In an ideal world this is what I want to do:

1. Keep my database model classes in separate files in their own directory.

2. Use them like this:

  c = model.client()   o = model.order()   s = model.staff() 

The only way I can see to do this is to put all my classes in a single file called model.py and save this at the root.

I’m sure I am missing something very basic here.

Answer 1

Python has two basic ways of importing content. Modules and Packages.

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A module is simply a python file on the include path: order.py

If order.py defines a class named foo, then access to that class could be had by:

import order o = order.foo() 

In order to use the syntax from the orignial question, you would need to ensure that your model.py file has the following attributes: [client, staff, order]

However, that typically means placing them in a single file. Which is what you are trying to avoid.

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A package is a directory with an __init__.py inside of it. The init.py initializes the package (ie. it is run on first import), and you can have either modules or sub-packages within that directory.

model     __init__.py     client.py     staff.py     order.py 

That way, to access any of the sub modules, you would simply say:

import model.client 

However, that is simply importing the module. It is not importing any of the attributes of the module. So in order to access a class inside the module, you would need to specify it:

import model.client o = model.client.clientclass()    

This is a bit tedious, but very well organized.

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Best of both (where performance isn’t a big deal):

If you type the following code in __init__.py:

from .client import clientclass as client from .staff import staffclass as staff from .order import orderclass as order 

Then you have auto-loaded all of your classes, and they can be accessed as:

import model c = model.client() s = model.staff() o = model.order() 

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In the end, it may be more simple to stick with the non-magical way to do it:

import model.client o = model.client.clientclass()    

–Gahooa