preg_match 匹配可选字符串，但不匹配所有字符串

Question

以以下正则表达式匹配为例。

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);

它产生以下内容：

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
)

但是，由于最后一个匹配是可选的，它也可以匹配以下“publisher/news/1/2010-march:03-23/test_title/1”。我的问题是，我希望能够匹配 (/page-[0-9]+) 如果存在，但仅匹配页码，因此“publisher/news/1/2010-march:03-23/test_title/ 1/page-1" 会像这样匹配：

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
)

我尝试了以下正则表达式

'!^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]+)?$!'

这有效，但它也会匹配“publisher/news/1/2010-march:03-23/test_title/1/1”。我不知道要进行一场比赛，但在比赛中却没有表现出来？在单个正则表达式中可能吗？

Answer 1

绝对不匹配 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]+))?$!

仍匹配 publisher/news/1/2010-march:03-23/ test_title/1/whatever 但忽略 /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 2

也许是这样的：

'!^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

这就是您正在寻找的正则表达式：

^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+))?

您可以在 rexexbuddy 中测试它。如果“page-1”未设置，则 var 9 将为空，否则将设置它。