News : Regular Expressions Support for ChangeDetect Power Filtering



Regular Expressions Support for ChangeDetect Power Filtering

ChangeDetect Releases Power Tools for Regular Expression Filtering of Web Content Changes.

ChangeDetect now supports regular expressions (regex) for complex pattern matching.

Regular expressions are a method of describing a pattern.

Regular expressions may be used to extract, for example, "all the lines that begin with the letter C" or "every 10-digit telephone number" or even "every sentence containing two commas, but no capital letter G".

Regular expressions are useful when tracking web content for changes because regular expressions allow powerful filtering criteria to be applied to downloaded content.

ChangeDetect members leverage regular expressions to filter extraneous content which limits change detection and notification to only pertinent data.

For example, with ChangeDetect regular expressions, members extract a listing for all image file references (i.e. .gif and .jpg) from a web page and then schedule the output for regular change monitoring.

Other common regular expression filtering examples are as follows:

By only considering relevant content, ChangeDetect users of regular expression filtering totally eliminate false alarms and the possibility for irrelevant notifications.

Regular expressions are truly the last word in filtering for relevent content when minding important changes on the web.

How to Get Started

Regular expression filtering is a very powerful tool that requires specialized "programmer-level" knowledge.

Regular expression filtering for web page change detection and notification is available for ChangeDetect "Plus" plan subscribers and above.

ChangeDetect users log into the member control panel and click the modify button for a previously created urlminder.

Then from the modify form, ChangeDetect users enter a well-formed regular expression.

All urlminders configured with regular expresson filtering should first be tested prior to implementation.

ChangeDetect includes a regular expression test tool from within the member control panel.

From the member control panel, click the test icon (test) and review sample web content after filtering.

If the regular expression contains syntax or logic errors, then the output from the test window will probably be incorrect or simply blank.

Regular expressions have a steep learning curve. If you do not already know how to program well-formed regular expressions, then you will need to either spend a lot of time researching the many resources on the internet or you will need to solicit professional help.

Basic ChangeDetect support provides only very limited assistance with regular expressions (regexp).

For advanced support options related to creating well formed regular expressions, contact ChangeDetect Managed Services.

The ChangeDetect Managed Services team is staffed with analysts who are experts at extracting relevant content changes from virtually any web page of interest.

ChangeDetect Staff

Published on April 10, 2004