'~(\s?(?P<weekday>Mon|Tue|Wed|Thu|Fri|Sat|Sun))[,]?\s?(?P<day>[0-9]{1,2})\s(?P<month>Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s(?P<year>[0-9]{4})\s(?P<hours>[0-9]{2}):(?P<minutes>[0-9]{2})(:(?P<seconds>[0-9]{2}))?\s(?P<timezone>[\+|\-][0-9]{4})\s?~'

(\s?(Mon|Tue|Wed|Thu|Fri|Sat|Sun))[,]?\s?([0-9]{1,2})\s(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s([0-9]{4})\s([0-9]{2}):([0-9]{2})(:([0-9]{2}))?\s([\+|\-][0-9]{4})\s?

This snippet is useful if you want to extract the relevant parts out of an Date header field of an email message. It was created according to the [RFC 5322 rules](http://tools.ietf.org/html/rfc5322#page-15 "RFC 5322, Page 15"). It supports named capturing groups for easier access of the date parts.

tested in PHP 5.2.6

2do:

* deal with obs-% data

Regular Expression, getting all parts of a E-Mail Date Header field

regex, regexp

Regular Expression