Pretty annoying when a programming language's constructs do things that are unintuitive, for example, Java substring:

str.substring(startIndex, endIndex); // oops, character at endIndex not included.

Or some other Python data science Google library (I used this at work) that decided their way is the best way, where they have a simple method but in the facade behind it is a nightmare monstrosity of complexity. How fun to debug or customize that!

Weird design decisions. They don't help because it makes them harder to immediately understand them.

To be fair, the end index is always exclusive, in any language.

@Lensflare I aim to find out why.

It's maybe more clear if you read it as length. "ABC"[0:1]>"a". Second parameter is just length and it starts from zero so. But also making the mistake still often. Can happen.

@whimsical that actually makes sense.
length = endIndex - startIndex

Top-exclusive ranges are the standard because they make more sense than bottom-exclusive ranges, and because making exactly one side of the range inclusive makes all sorts of math a lot easier. If both ends were included, an empty slice would have to be either unrepresentable or it would be encoded as end + 1 = start where neither end nor start are actually included.

@lorentz I knew it would be math. lol. It reminded me of (,] and [,) notations.

@jestdotty or simply do rand() % numberOfThings
🤨

@jestdotty Yes indeed.. learning by practice and experience always works well.

@jestdotty no, what you said was
(int)(randomFloat() * numberOfThings)

where randomFloat() gives you a number in the range of 0.0 to 1.0

Now thinking about it, I wonder though if there's a broad category of problems where it's useful to represent ranges with A..B containing X where (B < X) == (X < A), which is to say, double-inclusive if A<B and double-exclusive if B<A.

On an additional tangent from my tangent, I wonder if it's feasible to conduct niche elimination via algebraic invariants this way, i.e. we know that a standard range has low<high, so you can tag a union of a range and anything that fits into two fewer bits than it by setting low.msb=1 and high.msb=0 and then populating the rest of the range with the alternatve value.

@lorentz I‘m not gonna pretend that I understand (I never do), but I like your thoughts.