Question

I want to write a function in Python that returns different fixed values based on the value of an input index.

In other languages I would use a switch or case statement, but Python does not appear to have a switch statement. What are the recommended Python solutions in this scenario?

Answer 1

Python 3.10 (2021) introduced the match–case statement, which provides a first-class implementation of a "switch" for Python. For example:

def f(x):     match x:         case 'a':             return 1         case 'b':             return 2         case _:             return 0   # 0 is the default case if x is not found 

The match–case statement is considerably more powerful than this simple example.

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If you need to support Python ≤ 3.9, use a dictionary instead:

def f(x):     return {         'a': 1,         'b': 2,     }[x]