Thank you. For some reason, I’ve always had immense trouble with index bound arithmetic (questions like: is this inclusive? Exclusive? Is ..0 a single element

Thank you. For some reason, I’ve always had immense trouble with index bound arithmetic (questions like: is this inclusive? Exclusive? Is ..0 a single element or none? What about ..=0?). I have to actively think about these as I do when telling East from West. North versus South is simply intuitive, no conscious thought needed. Weird effect. Glad to see I wasn’t wrong in stumbling over this particular one.