Variables, Arrays, Constants and  Data Types

You often need to store values temporarily when performing calculations with VBScript. For example, you might want to calculate several values, compare them, and perform different operations on them, depending on the result of the comparison.

Variable names follow the standard rules for naming anything in VBScript. A variable name:

' Examples

ApplesSold = 10 ' The value 10 is passed to the variable.

ApplesSold = ApplesSold + 1 ' The variable is incremented.

Arrays allow you to refer to a series of variables by the same name and to use a number (an index) to tell them apart. This helps you create smaller and simpler code in many situations, because you can set up loops that deal efficiently with any number of cases by using the index number.

' Example

Dim A(10)

A(0) = 256

A(1) = 324

A(2) = 100

' ...

A(10) = 55
 

LBound Function

Returns the smallest available subscript for the indicated dimension of an array.

Syntax

LBound (arrayname [,dimension ] )

UBound Function

Returns the largest available subscript for the indicated dimension of an array.

Syntax

UBound (arrayname [,dimension ] )

' Example

Dim A(100,3,4)

UBound(A,1) ' returns 100

UBound(A,2) ' returns 3

UBound(A,3) ' returns 4

A Const statement can represent a mathematical or date/time quantity:

' Example

Const conPi = 3.14159265358979

VBScript has only one data type called a Variant. A Variant is a special kind of data type that can contain different kinds of information, depending on how it is used. Because Variant is the only data type in VBScript, it is also the data type returned by all functions in VBScript.

Variant Subtypes

Beyond the simple numeric or string classifications, a Variant can make further distinctions about the specific nature of numeric information. For example, you can have numeric information that represents a date or a time. When used with other date or time data, the result is always expressed as a date or a time. You can also have a rich variety of numeric information ranging in size from Boolean values to huge floating-point numbers. These different categories of information that can be contained in a Variant are called subtypes. Most of the time, you can just put the kind of data you want in a Variant, and the Variant behaves in a way that is most appropriate for the data it contains.

The following table shows subtypes of data that a Variant can contain.