* '''Warning:''' Do not use negative upper array index values as an "Out of Memory" [[ERROR Codes|error]] (or global Operating System errors) will occur.'''
* Use [[_PRESERVE]] before [[SHARED]] or an "invalid variable name" error will occur.
''Example 1:'' Changing the upper and lower array bounds
{{CodeStart}} '' ''
{{Cl|REDIM}} a(5 {{Cl|TO}} 10) ' create array as dynamic using REDIM
a(5) = 123
{{Cl|REDIM}} {{Cl|_PRESERVE}} a(20 {{Cl|TO}} 40)
{{Cl|PRINT}} a(20)
{{CodeEnd}}
:''Explanation:'' a(20) is now the 123 value a(5) was. The upper or lower bounds of arrays can be changed, but the type cannot. New array indices like a(40) are null(0) or empty strings. If the array element count is not reduced, all of the data will be preserved.
''Example 2:'' Sizing an array while storing file data.
{{CodeStart}} '' ''
{{Cl|REDIM}} Array$(1) 'create a dynamic string array