preg_match to match an optional string, but not match all of the string

Question

Take for example the following regex match.

preg_match('!^publisher/([A-Za-z0-9\-\_]+)/([0-9]+)/([0-9]{4})-(january|february|march|april|may|june|july|august|september|october|november|december):([0-9]{1,2})-([0-9]{1,2})/([A-Za-z0-9\-\_]+)/([0-9]+)(/page-[0-9]+)?$!', 'publisher/news/1/2010-march:03-23/test_title/1/page-1', $matches); 
print_r($matches);

It produces the following:

Array
(
    [0] => publisher/news/1/2010-march:03-23/test_title/1/page-1
    [1] => news
    [2] => 1
    [3] => 2010
    [4] => march
    [5] => 03
    [6] => 23
    [7] => test_title
    [8] => 1
    [9] => /page-1
)

However as the last match is optional it can also work with matching the following "publisher/news/1/2010-march:03-23/test_title/1". My problem is that I want to be able to match (/page-[0-9]+) if it exists, but match only the page number so "publisher/news/1/2010-march:03-23/test_title/1/page-1" would match like so:

Array
(
    [0] => publisher/news/1/2010-march:03-23/test_title/1/page-1
    [1] => news
    [2] => 1
    [3] => 2010
    [4] => march
    [5] => 03
    [6] => 23
    [7] => test_title
    [8] => 1
    [9] => 1
)

I've tried the following regex

'!^publisher/([A-Za-z0-9\-\_]+)/([0-9]+)/([0-9]{4})-(january|february|march|april|may|june|july|august|september|october|november|december):([0-9]{1,2})-([0-9]{1,2})/([A-Za-z0-9\-\_]+)/([0-9]+)/?p?a?g?e?-?([0-9]+)?$!'

This works, however it will also match "publisher/news/1/2010-march:03-23/test_title/1/1". I have no idea to perform a match but not have it come back in the matches? Is it possible in a single regex?

Answer 1

maybe like that:

'!^publisher/([A-Za-z0-9\-\_]+)/([0-9]+)/([0-9]{4})-(january|february|march|april|may|june|july|august|september|october|november|december):([0-9]{1,2})-([0-9]{1,2})/([A-Za-z0-9\-\_]+)/([0-9]+)(/page-([0-9]+))?$!'

Answer 2

To absolutely not match publisher/news/1/2010-march:03-23/test_title/1/whatever

!^publisher/([A-Za-z0-9\-\_]+)/([0-9]+)/([0-9]{4})-(january|february|march|april|may|june|july|august|september|october|november|december):([0-9]{1,2})-([0-9]{1,2})/([A-Za-z0-9\-\_]+)/([0-9]+)(?:/page-([0-9]+))?$!

To still match publisher/news/1/2010-march:03-23/test_title/1/whatever but ignore the /whatever:

!^publisher/([A-Za-z0-9\-\_]+)/([0-9]+)/([0-9]{4})-(january|february|march|april|may|june|july|august|september|october|november|december):([0-9]{1,2})-([0-9]{1,2})/([A-Za-z0-9\-\_]+)/([0-9]+)(?:(?:/page-([0-9]+))|/.*)?$!

Answer 3

This is the regex what you are looking for:

^publisher/([A-Za-z0-9\-\_]+)/([0-9]+)/([0-9]{4})-(january|february|march|april|may|june|july|august|september|october|november|december):([0-9]{1,2})-([0-9]{1,2})/([A-Za-z0-9\-\_]+)/([0-9]+)/(?:page-(\d+))?

You can test it in rexexbuddy. If "page-1" is not set it will leave var 9 empty else it will set it.