Regex quantified capture - php

Question

php > preg_match("#/m(/[^/]+)+/t/?#", "/m/part/other-part/t", $m);
php > var_dump($m);
array(2) {
[0]=>
string(20) "/m/part/other-part/t"
[1]=>
string(11) "/other-part"
}
php > preg_match_all("#/m(/[^/]+)+/t/?#", "/m/part/other-part/t", $m);
php > var_dump($m);
array(2) {
[0]=>
array(1) {
[0]=>
string(20) "/m/part/other-part/t"
}
[1]=>
array(1) {
[0]=>
string(11) "/other-part"
}
}
With said example I would like the capture to match both /part and /other-part, unfortunately with regex /m(/[^/]+)+/t/? doesn't capture both, as I expect.
This capture should not be bound to only match this sample, it should capture an undefined number of repetitions of the capture group; e.g. /m/part/other-part/and-another/more/t
UPDATE:
Given that this is expected behavior my question stands as of how I would be able to achieve this matching of mine?

Answer 1

Try this one out:
preg_match_all("#(?:/m)?/([^/]+)(?:/t)?#", "/m/part/other-part/another-part/t", $m);
var_dump($m);
It gives:
array(2) {
[0]=>
array(3) {
[0]=>
string(7) "/m/part"
[1]=>
string(11) "/other-part"
[2]=>
string(15) "/another-part/t"
}
[1]=>
array(3) {
[0]=>
string(4) "part"
[1]=>
string(10) "other-part"
[2]=>
string(12) "another-part"
}
}
//EDIT
IMO the best way to do what you want is to use preg_match() from #stema and explode result by / to get list of parts you want.

Answer 2

Thats the way capturing groups are working. repeated capturing groups have only the last match stored after the regex finished. Thats in your test "/other-part".
Try this instead
/m((?:/[^/]+)+)/t/?
See it here on Regexr, while hovering over the match, you can see the content of the capturing group.
Just make your group non-capturing by adding a ?: at the start and put another one around the whole repetition.
In php
preg_match_all("#/m((?:/[^/]+)+)/t/?#", "/m/part/other-part/t", $m);
var_dump($m);
Output:
array(2) {
[0]=> array(1) {
[0]=>
string(20) "/m/part/other-part/t"
}
[1]=> array(1) {
[0]=>
string(16) "/part/other-part"
}
}

Answer 3

As already written in a comment, you can't do this at once because preg_match does not allow you to return the same subgroup matches as well (like you can do with Javascript or .Net, see Get repeated matches with preg_match_all()). So you can divide the operation onto multiple steps:
Match the subject, extract the part you're interested in.
Match the interested part only.
Code:
$subject = '/m/part/other-part/t';
$subpattern = '/[^/]+';
$pattern = sprintf('~/m(?<path>(?:%s)+)/t/?~', $subpattern);
$r = preg_match($pattern, $subject, $matches);
if (!$r) return;
$r = preg_match_all("~$subpattern~", $matches['path'], $matches);
var_dump($matches);
Output:
array(1) {
[0]=>
array(2) {
[0]=>
string(5) "/part"
[1]=>
string(11) "/other-part"
}
}