Preserve

Used with ReDim to preserve contents will resizing an array

Syntax
   ReDim Preserve array(...) [As datatype]

Description
   Used with ReDim so that when an array is resized, data is not reset but 
   is preserved. This means when the array is enlarged that only new data 
   is reset, while the old data remains the same (but not necessarily at 
   the same absolute addresses in memory).

   NOTE: ReDim Preserve may not work as expected in all cases:
      Preserve's current behavior is to keep the original data contiguous 
      in memory, and only expand or truncate the size of the memory (if 
      resizing is not possible, the whole original data block is first 
      shifted to another memory location).
      Its behavior (with a single dimension) is well-defined only when the 
      upper bound is changed.  If the lower bound is changed, the current 
      result is that the data is in effect shifted to start at the new 
      lower bound.
      If there are multiple dimensions, only the upper bound of only the 
      first dimension may be changed safely.  If the first dimension is 
      reduced, the existing mappable data may be lost.  If lower-order 
      dimensions are resized at all, the effects can be hard to predict 
      (because multidimensional arrays are stored in row-major order : 
      values differing only in the last index are contiguous).

Example
   ReDim array(1 To 3) As Integer
   Dim i As Integer

   array(1) = 10
   array(2) = 5
   array(3) = 8

   ReDim Preserve array(1 To 10)

   For i = 1 To 10
      Print "array("; i; ") = "; array(i)
   Next

Differences from QB
   * Preserve wasn't supported until PDS 7.1

See also
   * Dim
   * LBound
   * ReDim
   * UBound

