Adopted one of answers from: http://stackoverflow.com/questions/5948051/regex-extract-twitterusername-from-url

Get Gmail tag, user and domain of an email address

This allows to the programer to match the time format groups, in a way that allow to discard some parts of the format. E.g. I have a format HhMmSs and i want to ignore the 'Ss' part from the format when I have no Seconds

Find any url('~filename.jpg'). URL must contain tilde

Everything, including proto, user:pass, host, query params and anchors

Unicode user name check with som allowed non-alhanum characters

Matches Portuguese phone numbers.

This breaks down an Apache2 access log into 9 parts. I use this for analyzing content in my webserver logs.

A pattern to match the email domain suffix

IP address with Subnet

Date in format MM-dd-yyyy