Introduction to VBS Regular Expressions - Using Regular Expressions

Using regular expressions

In typical search and replace operations, you must provide the exact text you are looking for. This technique may be sufficient for simple search and replace tasks in static text, but its lack of flexibility makes searching dynamic text difficult or even impossible.

Using regular expressions, you can:

Test a pattern in a string. For example, you can test an input string to see if a phone number pattern or a credit card number pattern exists in the string. This is called data validity verification.

Replacement text. You can use a regular expression to identify specific text in a document, which can then be deleted entirely or replaced with other text.

Extracts a substring from a string based on a pattern match. Can be used to find specific words in a text or input field.

For example, if you need to search the entire

web

site to remove some outdated material and replace some HTML

formatting tag, you can use regular expressions to test each file to see if the material you are looking for or

HTML

formatting tag exists in the file. Using this method, you can narrow down the affected files to those that contain the material that you want to delete or change. Regular expressions can then be used to remove obsolete material, and finally, regular expressions can be used again to find and replace those tags that need to be replaced.

Another example of how regular expressions can be useful is in a language whose string-handling capabilities were not yet known. VBScript

is a subset of

Visual

Basic

and has rich string processing functions. Similar to

Visual

Basic

Scripting

Edition

Does not have this ability. Regular expressions bring string processing capabilities to

Visual

Basic