by Leon Rosenshein

0, 1, Many

Continuing on with looking at numbers, think about counting. We all know how to count. Or we think we do. But do we really think about how we should be counting. Consider the following quote.

“Common programmer thought pattern: there are only three numbers: 0, 1, and n.”     – Joel Spolsky

There’s more than a little truth to that statement. After all, from a linguistic standpoint there’s lots of precedent for it. My non-linguistic experience also tells me that there’s not just a quantitative difference between 0 and 1 and N, but there’s also a qualitative difference.

The qualitative difference shows up in many different ways. 0 is the same as never. That can’t/doesn’t happen, so don’t worry about it. 1 is the same as always. Count on it happening. Assume it already happened. Either way, always or never, 1 or 0, TRUE, or FALSE, it’s a constant. There are no decisions needed. N, on the other hand, is maybe. You don’t know. It might happen. It might not. You can’t count on it. You need to handle it happening. You need to handle it NOT happening. Be prepared for both cases1.

Another qualitative difference is that when there is a choice, it’s often not either/or, but one (or more) of many. In code that shows up as something that started as if/else, but eventually morphed into a series of if/elseif/elseif/elseif/…/else. Sure, that can work, but there are better ways. Listen to your data and let it guide you in your programming. This is where object-oriented programming, in it’s true sense, really comes into it’s own. You make the decision early about what the object is, then you just act on/with it in a linear sense. You get back to always (or never) for most decisions and let the object worry about what it means in that specific case.

Then there’s the learning case. I’ve said before that versions 1 and 2 of something are easy. It’s when you get to version N that things get interesting. Again, that first version is the never case. No one has done it before, so there are no special cases. Just do something and it will be ok. Version 2 is the always case. For anyone who has used version 1, it’s always been that way. There’s no ambiguity. Everyone, on both sides, knows what to expect. It’s only when you get the version 3+ that you get into the maybe case. You don’t know what your customer has experienced. You don’t know what they expect. They don’t know what is coming from you. And as I’ve said, that’s where the learning is. Dealing with the ambiguity is where you stretch and grow.

So, whether you’re thinking about your design, your implementation, your career, or life in general, think about how you deal with counting.

  1. Hint. You might think it’s a 0/1 situation, but check your assumptions. It might be a 0/1 situation, but our assumptions are often wrong, so think them through ↩︎