vectors are basically arrays, but mathematically they are determined by a point, an angle, and a length, and so operations on them in math are based on that length. so a vector class would be like a list, but its contents would be generated based on a variable length, and you wouldn't be able to alter the contents therein directly. In a perfect world where truly immutable collections existed

so if you're doing operations with vectors and you just want to perform arithmetic with a portion of an existing vector, you could use

subVector

, as I proposed instead of constantly instantiating new objects.

that's the thought process at least

Also

...mathematically [vectors] are determined by a point, an angle, and a length...

I think you're confusing representation and definition. That is just a representation of the vector, and it's just as valid to represent it using starting and ending coordinates (and is often quite useful as it allows for easy matrix operations).