Regular expressions are one of those places where people "re-invent the wheel" a lot.  The <a href="http://msdnwiki.microsoft.com/en-us/mtpswiki/kweb790z.aspx">Regular Expression Examples</a> page is nice, but what I would really like to see is a page with a lengthy, categorized, list of commonly needed regular expressions.  E.G. parsing a time string into hours, minutes, and seconds.  Matching floating-point numbers, splitting a string on whitespace, etc.

 

There are some good websites out there with regular expression libraries, but with the number of different Regex engines out there in the world, it can be difficult to know whether a regex you find that's advertised as doing what you want will actually do that same thing when used in the .NET Regex class.  This topic seems like the right place for Microsoft to establish a library of .NET-compatible regular expressions.

-- JasonBl, MSFT

Some Common Regular Expressions:

1. Phone Number
   ^\d{3}-\d{3}-\d{4}$
   Example: 123-456-7890
2. US Zip Code
   ^\d{5}$
   Example: 12345
3. US Zip Code +4
   ^\d{5}-\d{4}$
   Example: 12345-7890
4. Email Address
   ^([0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,9})$
   Example: william.rawls@gmail.com
5. Email Address
   \w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*
   This is another example and it works great. Also it can be used for JAVA.
6. USA Social Security Number (SSN)
   ^\d{3}-\d{2}-\d{4}$
   Example: 555-22-9999

Regular Expressions, in particular .NET Regular Expressions, are supported fully by PowerShell via the -MATCH operator. The syntax of -MATCH is:

<string> -match <regular expression>

For example:

"Thomas Lee" -match "Lee"

The result of this would, of course, be $true.

In pages within this section, you'll find additional examples of regular expressions with Powershell.