What Regular Expressions Are and How You Can Benefit from Using Them
Regular expressions are used for searching through (usually textual) data. They allow you to search for pieces of text that match a certain form, instead of searching for a piece of text identical to the one you supply. For example, the regular expression [0-9]+ allows you to search through a file for any integer number.
It takes some time to get used to the syntax used by regular expressions. In our example, we used square brackets to create the character set [0-9]. This character set matches any character that is a digit. The + means that the character set must be matched as many times as possible, and at least once. PowerGREP’s documentation contains a detailed regular expression tutorial. The tutorial clearly explains the entire regular expression syntax. You will also find many detailed examples stepping you through the entire process of creating both simple and complex regular expressions.
Easily Create Regular Expressions
Two tools can make it easy for you to create regular expressions for use with PowerGREP and other applications. If you’re completely new to regular expressions or if you have enough experience to have become allergic to the cryptic regular expression syntax, take a look at RegexMagic. RegexMagic generates regular expressions to your specifications. You don’t have to deal with the regular expression syntax at all.
If you are already familiar with regular expressions or you want to learn to use the regular expression syntax directly, take a look at RegexBuddy. RegexBuddy can analyze any regular expression you type or paste in and continuously updates test results as you edit your regular expression, giving you the feedback you need to make sure your regex does what you want.
“I like the use of proper Perl regex, so I don’t have to remember some special proprietary syntax variation.”
“I must also compliment you on your very helpful manual
, especially on the tricky subject of regular expressions. Too often supplied documentation for such things are substandard or badly written, riddled with grammatical errors, etc.”
— Martin Andersen
14 February 2003, Australia
How You Can Use Regular Expressions
Many applications these days support regular expressions. With PowerGREP, you can search through files and folders on your computer or network, edit and redact files with search and replace operations, and collect information from files, all using regular expressions. PowerGREP’s regular expression engine is fully compatible with popular regex flavors such as those used by Perl, Java and the .NET framework.
When you learn how to use regular expressions, you will gain a valuable new skill that will come in handy in many situations. Many popular applications, such as the EditPad Pro text editor or the AceText information manager, allow you to use regular expressions in their search and replace features.
If you are a programmer, you can save a lot of programming effort with regular expressions. How often did you write some code to parse a string? With a regular expression, you can do in a couple of lines of code what would otherwise require dozens of lines, and save coding and debugging time. You can easily test the regular expressions in an editor like EditPad Pro or a specialized regular expression tool like RegexBuddy, before putting it into your code.
Regular Expressions Information Center
Jan Goyvaerts, chief designer of PowerGREP, has created a comprehensive web site covering almost everything there is to know about regular expressions at http://www.regular-expressions.info. The site boasts a regular expression quick start, acomprehensive regex tutorial, plenty of regex examples and a concise regex reference.
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