问题
The title is pretty much self-explanatory: When should one use the double-dots .. and when the triple-dots ...? Both are used to indicate a range.
回答1:
While ranges with double dots don't include the end bound, triple dots were used for inclusive ranges, i.e. (0...2) would contain 2 as well. This is now obsolete; use ..= for this purpose instead.
来源：https://stackoverflow.com/questions/53610214/what-is-the-difference-between-and