Switch Statement in Python?

Recently I am being presented with more opportunities to program in Python. As a result, I am learning more about the language, some of its core modules and packages, how it interacts with the operating system, etc.

Yesterday I discovered something I so useful that I would like to share it. This something is Python's equivalent of a switch statement.

It is not something particularly obscure, but it showcases a feature of the language that I found interesting.

For my job here at the uni I needed to run some scripts on corpora from 4 different languages. I decided to automate the process. Hence I created one main script that would call on the a respective subscript depending on which language was being processed. This meant that I was dealing with at least 4 cases (5, if I wanted to catch potential bugs when no language was specified for some reason).

Unlike the C family or Java, Python does not have the explicit construction switch{ case1 -> A, case2 -> B, caseN -> alpha} and the official solution, the use of elif-s namely, isn't very elegant and can be somewhat tedious to write. According to this PEP, there was not enough support for an explicit switch statement among coders, and now that I have discovered the alternative solution, I don't blame them.

At the time, however, I was still unenlightened and thus turned to Google that through its magic spewed out this page at the top of the results. When I searched for "python switch statement" again before writing this post, I also found a very humble and short description here, and also a python mailing list topic where it is mentioned.

It was by the concept introduced there that I found interesting. Turns out, it is possible to store any defined aliases as dictionary values. This includes, importantly, method and module names and even lambdas. This means that to emulate a switch statement, all one needs to do is create a dictionary with the keys representing the different cases and the values the respective procedures and then simply reference these procedures using the keys.

I hope that as I continue to write more code I will keep discovering neat things like this as I go. They make one's day sometimes.