Question

我想解析这个字符串并获取特殊值要解析的字符串具有其中一种模式

app/(integer)/(integer)/(text or null)
app/(integer)/(text or null)
app/(text or null)

我可以使用preg_match进行简单使用，但我无法编写可选参数

preg_match('%app/(\d+)/(\d+)/(\.*)$%', $text, $matches)

Answer 1

您给定的模式会导致您想要匹配的以下情况：

app/1/2/foo
app/1/2/
app/1/bar
app/1/
app/bar
app/

这可以使用带有OR运算符（|）的正则表达式来实现。语法如下：

~app/(\d+)/(\d+)/(\w+)|app/(\d+)/(\d+)/|app/(\d+)/(\w+)|app/(\d+)/|app/(\w+)|app/$~

我为你的情况建立了一个regex101“小提琴”： http://regex101.com/r/zT9jT6/1

请注意，“app /”将匹配$ matches数组中的0个条目。

etvoilà。

Answer 2

我做：

$urls = array(
    'app/12/34/text',
    'app/12/34/',
    'app/56/text',
    'app/56/',
    'app/text',
    'app/',
);
foreach ($urls as $url) {
    preg_match( "#app/(?:(\d+)/)?(?:(\d+)/)?(.*)#", $url, $m);
    print_r($m);
}

<强>输出：

Array
(
    [0] => app/12/34/text
    [1] => 12
    [2] => 34
    [3] => text
)
Array
(
    [0] => app/12/34/
    [1] => 12
    [2] => 34
    [3] =>
)
Array
(
    [0] => app/56/text
    [1] => 56
    [2] =>
    [3] => text
)
Array
(
    [0] => app/56/
    [1] => 56
    [2] =>
    [3] =>
)
Array
(
    [0] => app/text
    [1] =>
    [2] =>
    [3] => text
)
Array
(
    [0] => app/
    [1] =>
    [2] =>
    [3] =>
)

PHP preg_match，带有可选的数学规则

2 个答案: