Just Use Dictionaries (Python) | Hacker News Reader

Just Use Dictionaries (Python)

davidvujic.blogspot.com

I used to be a strong proponent of this, but I tend to use dataclasses more and more with time. Still use a lot of dicts, lists, and sets, but mostly as collections, rarely to hold one single element data.

It came naturally, not out of some design, but I guess having better and better typing support everywhere makes it more and more convenient.

Sounds like a good balance between the approaches!

I usually would prefer having everything behind the endpoint (such as Pydantic schemas & FastAPI) as simple dicts and lists.

I like the simplicity but there are some social problems with this. Let's say that I work on a team which has codebases with classes/dataclasses and I add a new codebase that doesn't use them, or one that doesn't _underscore just about everything - the first thing that will come up in the code review is questions about why I'm doing things differently, and I wouldn't have a good reason apart from the fact that I find it more aesthetically pleasing.

I agree on that it is a good idea to use patterns that the teams have agreed on.

Would you do the same if you were about to make changes in a code base with only dictionaries and lists in it? :)

> A Python dictionary has a simple & well-known API.

Actually it doesn't.

I was referring to the simplistic and well-known way of accessing data from a dictionary, such getting the value for a specific key or even iterating the keys & values of a dictionary. There's also quite simple to merge several dictionaries, or even pick/omit to only work with the data that is actually needed in the actual context. What's your thoughts about that?

Thanks for asking.

It is simple.

It is not simplistic. It is not an API.

What is it then?

As you said. A way of accessing data from a dictionary. Or more generally, a language feature.

Would you agree that it is well-known and simple?

Yes!

Except when you need Pandas dataframes or Apache Arrows

I haven’t used those tools, but I guess you would use the data types already defined in them and what is returned from the functions in there?

If you were about to pass on the result from a calculation to somewhere else, a dictionary or list would probably be a good idea. You probably wouldn’t want the entire system be aware of a Pandas specific data type.

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