VBScript » Objects » RegExp

VBScript » Objects » RegExp

The RegExp object is used to look for and match all occurrences of a search string pattern inside a target string.

Each time the RegExp object finds a match during the search, a Match object is created and added to a Matches collection.

The search pattern is declared using the Pattern property. It could, for example, be a simple string, such as "cost analysis". However, the search pattern can also be a regular expression. Regular expressions can range from being very simple to being extremely complex. The Pattern property page contains an introductory listing of special characters that can be used with regular expressions.

Examples

Code:

<% 
'this sub finds the matches 
Sub RegExpTest(strMatchPattern, strPhrase) 
'create variables 
Dim objRegEx, Match, Matches, StrReturnStr 
'create instance of RegExp object 
Set objRegEx = New RegExp 
'find all matches 
objRegEx.Global = True 
'set case insensitive 
objRegEx.IgnoreCase = True 
'set the pattern 
objRegEx.Pattern = strMatchPattern 
'create the collection of matches 
Set Matches = objRegEx.Execute(strPhrase) 
'print out all matches 
For Each Match in Matches 
strReturnStr = "Match found at position " 
strReturnStr = strReturnStr Match.FirstIndex ". Match 
Value is '" 
strReturnStr = strReturnStr Match.value "'." 
'print 
Response.Write(strReturnStr "<BR>") 
Next 
End Sub 
'call the subroutine 
RegExpTest "is.", "Is1 is2 Is3 is4" 
%>

Output:

Match found at position 0. Match Value is 'Is1'. Match found at position 4. Match Value is 'is2'. Match found at position 8. Match Value is 'Is3'. Match found at position 12. Match Value is 'is4'.

Explanation:

The following code is a simpler, working version of a program published by Microsoft. Note the use of the keyword New when you create a RegExp object using Set.

Properties

Global

Syntax: object.Global = [ True | False ]

This property is only used with a RegExp object variable and returns a Boolean value. False signifies that a search should only find the first occurrence of a match. True signifies that a search should find all occurrences of a match.

IgnoreCase

Syntax: object.IgnoreCase

This property is only used with a RegExp object variable and returns a Boolean value. False signifies that a search should be case-sensitive (i.e., upper versus lower case). True signifies that a search should ignore case in a match.

Pattern

Syntax: object.Pattern

This property defines the regular expression or search pattern string that is to be matched during the search.

Methods

Execute

Syntax: object.Execute (TargetString)

This method is used to execute the search and to look for matches of the search pattern string (or regular expression) and the target string. Each time a match is made, a Match object is created and added to a collection that is called a Matches collection. Syntax: object.

Replace

Syntax: object.Replace (String1, String2)

This method is used to replace text found in a regular expression search. Do not confuse this method with the Replace function.

Test

Syntax: object.Test

This method is used to determine if the search pattern occurs within a specified string and returns a Boolean value to signify the results of the search. True is returned if the pattern is found. Otherwise, False is returned.