Extract multiples strings from one variable by using preg_match - php

Question

I'm having troubles extracting several strings between tags from a variable, in order to echo them inside a span individually.
Thing is, the tags in question are determined by a variable, here is what it looks like :
<?php
$string = "[en_UK]english1[/en_UK][en_UK]english2[/en_UK][fr_FR]francais1[/fr_FR][fr_FR]francais2[/fr_FR][fr_FR]francais3[/fr_FR]";
$lang = "en_UK";
preg_match("/(.[$lang]), (.[\/$lang])/", $string, $outputs_list);
foreach ($outputs_list as $output) {
echo "<span>".$output."/span>";
}
// in this exemple I want to output :
// <span>english1</span>
// <span>english2</span>
?>
It's my first time using preg_match and after trying so many differents things I'm kinda lost right now.
Basically I want to extract every strings contained between the tags [$lang] and [/$lang] (in my exemple $lang = "en_UK" but it will be determined by the user's cookies.
I'd like some help figuring this out if possible,
Thanks

Answer 1

[] in a regular expression makes a character class. I'm not sure what you're trying to do with the .s and , either. Your regex currently says:
Any single character, an e, n, _, U, or K, a , and space, and again any single character, an e, n, _, U, K, but this time also allowing /.
Regex demo: https://regex101.com/r/8pmy89/2
I also believe you were grouping the wrong value. The () go around what you want to capture, know as a capture group.
I think the regex you want is:
\[$lang\](.+?)\[\/$lang\]
Regex demo: https://regex101.com/r/8pmy89/3
PHP Usage:
$string = "[en_UK]english1[/en_UK][en_UK]english2[/en_UK][fr_FR]francais1[/fr_FR][fr_FR]francais2[/fr_FR][fr_FR]francais3[/fr_FR]";
$lang = "en_UK";
preg_match_all("/\[$lang\](.+?)\[\/$lang\]/", $string, $outputs_list);
foreach ($outputs_list[1] as $output) {
echo "<span>".$output."/span>";
}
PHP demo: https://eval.in/686086
Preg_match vs. preg_match_all
Preg_match only returns the first match(es) of a regex. Preg_match_all returns all matches of the regex. The 0 index has what the full regex matched. All subsequent indexes are each capture groups, e.g. 1 is the first capture group.
Simple Demo: https://eval.in/686116
$string = '12345';
preg_match('/(\d)/', $string, $match);
print_r($match);
preg_match_all('/(\d)/', $string, $match);
print_r($match);
Output:
Array
(
[0] => 1
[1] => 1
)
^ is preg_match, below is the preg_match_all
Array
(
[0] => Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
)
[1] => Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
)
)

Answer 2

I made little late to post this answer. #chris already answered your question, so i made the solution broad which might help other users who may have different requirements.
<?php
$string = "[en_UK]english1[/en_UK][en_UK]english2[/en_UK][fr_FR]francais1[/fr_FR][fr_FR]francais2[/fr_FR][fr_FR]francais3[/fr_FR]";
$lang = "en_UK";
echo "User Language -";
preg_match_all("/\[$lang\](.+?)\[\/$lang\]/", $string, $outputs_list);
foreach ($outputs_list[1] as $output) {
echo "<span>".$output.",</span>";
}
echo "<br/>All languages - ";
//if all lang
preg_match_all("/[a-zA-Z0-9]{3,}/", $string, $outputs_list);
foreach ($outputs_list[0] as $output) {
echo "<span>".$output.",</span>";
}
echo "<br/>Type of lang - ";
//for showing all type of lang
preg_match_all("/(\[[a-zA-Z_]+\])*/", $string, $outputs_list);
foreach ($outputs_list[1] as $output) {
echo "<span>".$output."</span>";
}
?>
OUTPUT
User Language -english1,english2,
All languages - english1,english2,francais1,francais2,francais3,
Type of lang - [en_UK][en_UK][fr_FR][fr_FR][fr_FR]