Can I create an array’s size dynamically?

VBScript's arrays have quite a few limitations. You may have noticed if you try this:

 

<%

    x = 15

    Dim demoArray(x)

%>

 

You get this error:

 

Microsoft VBScript compilation (0x800A0402)

Expected integer constant

 

To work around this, you need to declare the array without a size (or with a constant size, e.g. 0), and then re-dimension it from the variable. Here are two examples; one using a simple array, the other a multi-dimensional array:

 

<%

    x = 15

    Dim demoArray()

    ReDim demoArray(x)

%>

 

<%

    x = 15

    y = 10

    Dim demoArray()

    ReDim demoArray(x,y)

%>

 

Note that if you want to increase the size of an array within a loop, and want to preserve the existing values assigned to the array, you need to use the Preserve keyword (otherwise, the array gets erased and re-created, thus destroying all your values):

 

<%

    Dim demoArray()

    for i = 1 to 5

        ReDim Preserve demoArray(i)

        DemoArray(i) = "test" & i

    next

%>