This is the second article following up Phillip J. Eby's Python Is Not Java. In the first article, The Static Method Thing, we took a look at how Java static methods differ from Python class/static methods. This time we're going to dive deep into the evils of getters and setters.

I'm hopping around a bit because this was the item that I saw the most confusion around in comments and trackback posts. I'm also a bit worried that some walked away with the impression that getters and setters are always evil and should never be used, ever, in any language, ever. Getters and setters are not GOTOs, and Phillip's original post never came close to making that claim.

Let's take a look at what Phillip had to say about getters and setter use in Python:

Getters and setters are evil. Evil, evil, I say! Python objects are not Java beans. Do not write getters and setters. This is what the 'property' built-in is for. And do not take that to mean that you should write getters and setters, and then wrap them in 'property'. That means that until you prove that you need anything more than a simple attribute access, don't write getters and setters. They are a waste of CPU time, but more important, they are a waste of programmer time. Not just for the people writing the code and tests, but for the people who have to read and understand them as well.

In Java, you have to use getters and setters because using public fields gives you no opportunity to go back and change your mind later to using getters and setters. So in Java, you might as well get the chore out of the way up front. In Python, this is silly, because you can start with a normal attribute and change your mind at any time, without affecting any clients of the class. So, don't write getters and setters.

I thought he explained this well. There's not a lot missing here so I'm going to dive real deep and try to give a lot of background and code examples on the situation.