Uses of Redim Preserve Keyword

In order to save the data in the array,  Preserve keyword is to be used.

Example

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'Initialize Dynamic array
Dim arr()

'In the brackets 2 is mentioned, this indicates the last index  of the array. 
'So  number of cells will be 3 as index starts from 0.

Redim arr(2) ' 

arr(0) = "Akash"
arr(1) = "Padam"
arr(2) = "Prashant"


'Re-dimension array as there is a need to delete last element from the array
'In the bracket 1 is mentioned indicating that the last cell index should be 1
'So there will be two elements in the array, at arr(0) and at arr(1)

ReDim arr(1) 

Msgbox arr(0) ' Return Empty
Msgbox arr(1) ' Return Empty


' If Preserve is not used array will be Re-Dimensioned, but existing values will be deleted
'In order to save the data, Preserve is to be used
'So the correct code will be:

ReDim Preserve arr(1) 

Msgbox arr(0) ' Return Akash 
Msgbox arr(1) ' Return Padam