Visual Basic and Visual FoxPro arrays
VBA
Dim, Redim
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VFP
Dimension, Declare, Local Array
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Visual Basic Syntax Notes
Visual Basic Arrays can be fixed or dynamic and their size can be
changed with the ReDim statment. Unless the
Option Base setting has been set to 1, VBA
arrays start from zero. This declaration:
Dim myNames(10) As String
will declare an array with 11 elements from myNames(0) to myNames(10). If this use of
zero as a base feels unfamiliar then you can either use
Option Base 1 to force VBA to start numbering from one or
you can explicitly set the range of the array:
Dimmy Names(1 To 10) As String
An array can have up to 60 dimensions but it is difficult to think of a use
for such a complex structure. It's also difficult to think of a computer that
could process even the smallest 60-dimensional 2x2x2x2x...x2x2x2x2 array - that's
around a million Tb.
Visual FoxPro Syntax Notes
Arrays in Fox are restricted to 2 dimensions but apart from that they
are very much more flexible than VBA arrays. For a start, the lack of data
types in VFP means that different elements of an array can hold
different types of information. The Scatter
command takes advantage of this by creating an array whose elements
hold the data from the fields of the current record.
FoxPro arrays are also unusual in that they can be resized at runtime
without loss of data. A 6 x 6 two-dimensional array can be resized as
as 12 x 2 or extended into a 3 x 5. Functions such as
AElement and
ASubscript allow you to refer to the elements
of any array as though it were a simple list.
FoxPro makes great use of arrays. The
Into Array clause in the VFP dialect of SQL
creates an array holding the set of results from the query. Functions
such as APrinter() and
AFont() return the printers and fonts
available respectively. Most of these functions start with "A" so they're
easy to find in Help.
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