VBScript Tutorials - Herong's Tutorial Notes
Dr. Herong Yang, Version 4.01

Array Declaration and Built-in Functions

Part:   1  2  3  4   5 

VB Script Tutorials - Herong's Tutorial Notes © Dr. Herong Yang

Data Types and Literals

Variables

Logic Operations

String Operations

Conditional Statements

Arrays

Loop Statements

Functions and Subroutines

Built-in Functions

Variable Inspection

... Table of Contents

(Continued from previous part...)

Here is the output: 

Is aSite an array? True
Lower bound of aPrime = 0
Upper bound of aPrime = 2
Web sites:
   yahoo
   netscape
   microsoft
   
   
   
   
   
   ibm

Noticed anything interesting? The example confirms that:

  • Arrays created with the "Array" function are dynamic-size arrays.
  • "For Each" statement creates a copy of the current element in the temporary variable. You can not update element values in this way. My "Updating array elements" code block updated only the temporary variable.

"Erase" Statements

It is interesting to know that VB offers a special statement called "Erase" to remove all values in an array: 

   Erase array_variable

If the specified array is a fixed-size array, it will reset all elements to the default value. If the specified array is a dynamic-size array, it will reset the array to zero size.

To show you how the "Erase" statements work, I wrote the following example, array_erase.html: 

<html>
<body>
<!-- array_erase.html
   Copyright (c) 2006 by Dr. Herong Yang. http://www.herongyang.com/
-->
<pre>
<script language="vbscript">

   ' Setting a fixed-size array
   Dim aFixed(1) 
   aFixed(0) = "Dog"
   aFixed(1) = "Cat"
   document.writeln("")
   document.writeln("Favorite pets:")
   For Each sItem In aFixed
      document.writeln("   " & sItem )
   Next

   ' Setting a dynamic-size array
   aDynamic = Array("Apple", "Orange")
   document.writeln("")
   document.writeln("Favorite fruits:")
   For Each sItem In aDynamic
      document.writeln("   " & sItem )
   Next

   ' Erasing arrays
   document.writeln("")
   document.writeln("Erasing arrays...")
   Erase aFixed
   Erase aDynamic

   ' Looking at arrays again
   document.writeln("")
   document.writeln("Pets left:")
   iCount = 0
   For Each sItem In aFixed
      iCount = iCount + 1
      document.writeln("   " & sItem )
   Next
   document.writeln("   Count = " & iCount)

   document.writeln("")
   document.writeln("Fruits left:")
   iCount = 0
   For Each sItem In aDynamic
      iCount = iCount + 1
      document.writeln("   " & sItem )
   Next
   document.writeln("   Count = " & iCount)
</script>
</pre>
</body>
</html>

(Continued on next part...)

Part:   1  2  3  4   5 

Dr. Herong Yang, updated in 2006
VBScript Tutorials - Herong's Tutorial Notes - Array Declaration and Built-in Functions