Question

Is there a function to determine length of a dynamic array in Delphi ?

Answer 1

Use Length function to get the length of your array:

var
  ArrayLength: Integer;
begin
  ArrayLength := Length(ArrayOfSomething);
  ...
end;

From the reference for this function (emphasized by me):

In Delphi code, Length returns the number of characters actually
used in the string or the number of elements in the array.