Matches all ips that points to localhost like, optionally capturing port number: 127.X.X.X and 127.X.X.X:

This regex matches roman numbers from 1 (I) to 3999 (MMMCMXCIX)

This pattern validates all the possible dates for all months in YYYY-MM-DD format. Due to limitations of regex it can not validate the dates of february for leap year. It will allow the date 29 for leap year too. Make sure to validate that yourself.

This pattern parses the yowsup-cli message output to recover (otherwise lost) messages. Current yowsup version: v2.4

Use this Regex for server-side validation also with some slight modifications like so for .NET -- @\w+([-+.']\w+)@\w+([-.]\w+)\.[a-zA-Z0-9]{2,6}(-.{2,6})*;

This is the javascript equivalent that .NET uses in their server-side validators.

get src url from img tag in html

Regex to constrain a text to have at least 2 strings. Compatible with 2nd-3rd-Nth names/surnames.

Grabs all HTML tags

In Ontario, Canada, license classes are combined on the drivers license. This regex will parse out individual classes from the combination.

http://regexone.com/problem/extracting_url_data