Avoiding global variables but also too many function arguments (Python)

Question

Let's say I have a python module that has a lot of functions that rely on each other, processing each others results. There's lots of cohesion.

That means I'll be passing back and forth a lot of arguments. Either that, or I'd be using global variables.

What are best practices to deal with such a situation if? Things that come to mind would be replacing those parameters with dictionaries. But I don't necessarily like how that changes the function signature to something less expressive. Or I can wrap everything into a class. But that feels like I'm cheating and using "pseudo"-global variables?

I'm asking specifically for how to deal with this in Python but I understand that many of those things would apply to other languages as well.

I don't have a specific code example right, it's just something that came to mind when I was thinking about this issue.

Examples could be: You have a function that calculates something. In the process, a lot of auxiliary stuff is calculated. Your processing routines need access to this auxiliary stuff, and you don't want to just re-compute it.

Answer 1

This is a very generic question so it is hard to be specific. What you seem to be describing is a bunch of inter-related functions that share data. That pattern is usually implemented as an Object.

Instead of a bunch of functions, create a class with a lot of methods. For the common data, use attributes. Set the attributes, then call the methods. The methods can refer to the attributes without them being explicitly passed as parameters.