function Copy(S: <string or dynamic array>; Index: Integer; Count: Integer): string;
Returns a substring of a string or a segment of a dynamic array.
S is an expression of a string or dynamic-array type. Index and Count are integer-type expressions. Copy returns a substring or subarray containing Count characters or elements starting at S[Index]. The substring or subarray is a unique copy (that is, it does not share memory with S; if the elements of the array are pointers or objects, these are not copied as well.)
If Index is larger than the length of S, Copy returns an empty string or array.
If Count specifies more characters or array elements than are available, only the characters or elements from S[Index] to the end of S are returned.