10.2.2 Vector
A Vector is an optimized fixed-length collection of elements. Much like Array, it has one type parameter and all elements of a vector must be of the specified type, it can be iterated over using a for loop and accessed using array access syntax. However, unlike Array and List, vector length is specified on creation and cannot be changed later.
class Main {
  static function main() {
    var vec = new haxe.ds.Vector(10);
    for (i in 0...vec.length) {
      vec[i] = i;
    }
    trace(vec[0]); // 0
    trace(vec[5]); // 5
    trace(vec[9]); // 9
  }
}
haxe.ds.Vector is implemented as an abstract type (Abstract) over a native array implementation for given target and can be faster for fixed-size collections, because the memory for storing its elements is pre-allocated.
See the Vector API for details about the vector methods.