VBScript Tutorials - Herong's Tutorial Examples - v6.02, by Herong Yang
"Erase" Statement - Removing All Elements in an Array
This section provides a tutorial example on how to use a 'Erase' statement to reset all elements to the default value in a fixed-size array, or truncate the size of a dynamic-size array to zero.
It is interesting to know that VBScript 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: "Empty". If the specified array is a dynamic-size array, it will reset the array to zero size.
To show you how an "Erase" statement works, I wrote the following example, array_erase.html:
<html> <body> <!-- array_erase.html - Copyright (c) 1998 HerongYang.com. All Rights Reserved. --> <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 Dim aDynamic() ReDim aDynamic(1) aDynamic(0) = "Apple" aDynamic(1) = "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>
Here is the output:
Favorite pets: Dog Cat Favorite fruits: Apple Orange Erasing arrays... Pets left: Count = 2 Fruits left: Count = 0
I don't see any surprises in the output. Do you?
Table of Contents
Introduction of VBScript - Visual Basic Scripting Edition
Variant Data Type, Subtypes, and Literals
Numeric Comparison Operations and Logical Operations
String Operations - Concatenation and Comparison
Variable Declaration and Assignment Statement
Expression and Order of Operation Precedence
Statement Syntax and Statement Types
►Array Data Type and Related Statements
"Dim x()" - Declaring Array Variables
"x(i)" - Accessing Array Elements with Indexes
"Dim x(n)" - Fixed-Size Array Example
"Dim x()" - Dynamic-Size Array Example
►"Erase" Statement - Removing All Elements in an Array
Data Type "Variant()" - Array of Variant Values
Array References and Array Assignment Statements
Conditional Statements - "If ... Then" and "Select Case"
Loop Statements - "For", "While", and "Do"
"Function" and "Sub" Procedures
Inspecting Variables Received in Procedures
Error Handling Flag and the "Err" Object
Regular Expression Pattern Match and Replacement
scrrun.dll - Scripting Runtime DLL Library
IE Web Browser Supporting VBScript