Qt's QList: which is the canonical form of getting the number of items in a list?

Question

Qt's QList class provides several methods for getting the number of items in the list - count, length, and size. As we all know, consistency is important, so which should be the canonical/preferred method to use of those 3?

Answer 1

The consistency you should work towards is within your project. You're not really going to gain anything by trying to be consistent with everyone else, unless there's some way they'd be incompatible.

That being said, there are subtle semantic differences (in English, not C++) between the names of the functions. If you can make your code clearer by taking advantage of the differences, then consistency may actually work against you.

Answer 2

I agree with everything @Cogwheel said, but in all honesty I would just pick one and stick with it. I think good style would dictate that if "size" sounds the best to you, then use "size" everywhere...don't alternate between "count", "length" and "size" haphazardly. That will lead to potential confusion or a lot of unnecessary trips to documentation pages.

You could try to come up with some other kind of rationale, but the language itself isn't even consistent. All the STL containers (e.g. list, vector) only provide "size", the string class provides "size" and "length", etc.

Pick your favorite (or if you have multiple developers, you should all agree on a favorite) and just stick with it.

Answer 3

IMHO, Any one of those. Since even different developers follow different functions within your project, the function names are quite self documented, in the sense that other developers can easily understand what the function is meant to.

Answer 4

I usually go with "size." Ultimately, it is a bit arbitrary, but Qt containers and STL containers both generally have a size, so it is easy to stay consistent between the two types. It's also the shortest. Whenever several solutions are basically equivalent, I always go with whichever results in the least amount of typing. It's a simple rule of thumb, so everybody on the project can usually remember it.