Array named capture using PHP regex - php

Question

If named capture matches multiple times, is it possible to retrieve all matches?
Example
<?php
$string = 'TextToMatch [some][random][tags] SomeMoreMatches';
$pattern = "!(TextToMatch )(?P<tags>\[.+?\])+( SomeMoreMatches)!";
preg_match($pattern, $string, $matches);
print_r($matches);
Which results in
Array
(
[0] => TextToMatch [some][random][tags] SomeMoreMatches
[1] => TextToMatch
[tags] => [tags]
[2] => [tags]
[3] => SomeMoreMatches
)
Is is possible to get something like
Array
(
[0] => TextToMatch [some][random][tags] SomeMoreMatches
[1] => TextToMatch
[tags] => Array
(
[0] => [some]
[1] => [random]
[2] => [tags]
)
[2] => Array
(
[0] => [some]
[1] => [random]
[2] => [tags]
)
[3] => SomeMoreMatches
)
using only preg_match?
I am aware that I can explode tags, but I wonder if I can do this with preg_match (or similiar function) only.
Other example
$input = "Some text [many][more][other][tags][here] and maybe some text here?";
Desirable output
Array
(
[0] => Some text [many][more][other][tags][here] and maybe some text here?
[1] => Some text
[tags] => Array
(
[0] => [many]
[1] => [more]
[2] => [other]
[3] => [tags]
[4] => [here]
)
[2] => Array
(
[0] => [many]
[1] => [more]
[2] => [other]
[3] => [tags]
[4] => [here]
)
[3] => and maybe some text here?
)

Answer 1

You need use preg_match_all and modify the reg exp:
preg_match_all('/(?P<tags>\[.+?\])/', $string, $matches);
Just remove the + after ) to set one pattern and preg_match_all make a global search
If you need the specific answer that you posted, try with:
$string = '[some][random][tags]';
$pattern = "/(?P<tags>\[.+?\])/";
preg_match_all($pattern, $string, $matches);
$matches = [
implode($matches['tags']), end($matches['tags'])
] + $matches;
print_r($matches);
You get:
Array
(
[0] => [some][random][tags]
[1] => [tags]
[tags] => Array
(
[0] => [some]
[1] => [random]
[2] => [tags]
)
)

Answer 2

Since you stated in your comments that you are not actually interested in the leading substring before the set of tags, and because you stated that you don't necessarily need the named capture group (I never use them), you really only need to remove the first bit, split the string on the space after the set of tags, then split each tag in the set of tags.
Code: (Demo)
$split = explode(' ', strstr($input, '['), 2); // strstr() trims off the leading substring
var_export($split); // ^ tells explode to stop after making 2 elements
Produces:
array (
0 => '[many][more][other][tags][here]',
1 => 'and maybe some text here?',
)
Then the most direct/clean way to split those square bracketed tags, is to use the zero-width position between each closing bracket (]) and each opening bracket ([). Since only regex can isolate these specific positions as delimiters, I'll suggest preg_split().
$split[0] = preg_split('~]\K~', $split[0], -1, PREG_SPLIT_NO_EMPTY);
var_export($split); ^^- release/forget previously matched character(s)
This is the final output:
array (
0 =>
array (
0 => '[many]',
1 => '[more]',
2 => '[other]',
3 => '[tags]',
4 => '[here]',
),
1 => 'and maybe some text here?',
)

Answer 3

No, as Wiktor stated(1, 2), it is not possible to do using only preg_match
Solution that just works
<?php
$string = 'TextToMatch [some][random][tags] SomeMoreMatches';
$pattern = "!(TextToMatch )(?P<tags>\[.+?\]+)( SomeMoreMatches)!";
preg_match($pattern, $string, $matches);
$matches[2] = $matches["tags"] = array_map(function($s){return "[$s]";}, explode("][", substr($matches["tags"],1,-1)));
print_r($matches);