PHP Preg Match, get value between specific pattern

Question

I have a php application that saves the following output on database:

::cck_gx::gx::/cck_gx::
::i1|0|gx::Lorem::/i1|0|gx::
::head1|0|gx::ipsum::/head1|0|gx::
::tx1|0|gx::dolor, fithos lusec.::/tx1|0|gx::
::cckend_gx::::/cckend_gx::
::cck_gx::gx::/cck_gx::
::i1|1|gx::calendar::/i1|1|gx::
::head1|1|gx::1 Fatura Grátis Por Ano::/head1|1|gx::
::tx1|1|gx::10% de cada mensalidade é reservado, e o valor acumulado até a renovação do Seguro Porto Seguro ou Azul Seguros, é devolvido em forma de desconto. Ou seja, Cliente Conecta pode ter uma fatura de celular grátis por ano.::/tx1|1|gx::

And I want to retrieve information from this output using preg_match. For example retrieving any value in the same place of "Lorem" and "ipsum" on the example below:

::i1|0|gx::Lorem::/i1|0|gx::
::head1|0|gx::ipsum::/head1|0|gx::

But I am clueless with preg_match syntax.

I understand that I will need a different preg match for each "label" (like a preg_match to retrieve all "i1" values, a different preg_match to retrieve all "head1" and so on). I just need one example that works to understand the correct pattern.

Also, in the last line is a example with a lot of different characters like numbers, commas, "%" and others, I am not sure if this will mess with syntax.

Here two of my failed attempts:

preg_match('~[::i1|0|gx::](.*?)[/::i1|0|gx::]~', $maindata->introtext, $match1a);
 preg_match('::i1|0|gx::(.*?)::/i1|0|gx::', $maindata->introtext, $match1a);
 preg_match('/::i1|0|gx::(.*?)::.i1|0|gx::/', $maindata->introtext, $match1a);

Answer 1

Hope this will help

<?php
    $str = '::i1|0|gx::Lorem::/i1|0|gx::';
    preg_match('/(?<=gx::).*(?=::\/)/', $str);

You can also use preg_match_all()

<?php
    $str = '::cck_gx::gx::/cck_gx::
    ::i1|0|gx::Lorem::/i1|0|gx::
    ::head1|0|gx::ipsum::/head1|0|gx::
    ::tx1|0|gx::dolor, fithos lusec.::/tx1|0|gx::
    ::cckend_gx::::/cckend_gx::
    ::cck_gx::gx::/cck_gx::
    ::i1|1|gx::calendar::/i1|1|gx::
    ::head1|1|gx::1 Fatura Grátis Por Ano::/head1|1|gx::';

    preg_match_all('/(?<=gx::).*(?=::\/)/', $str, $matches);
    var_dump($matches);

(?<=gx::) Positive Lookbehind - Assert that the regex below can be matched

. matches any character (except newline)

* Between zero and unlimited times, as many times as possible

(?=::\/) Positive Lookahead - Assert that the regex below can be matched

:: matches the characters :: literally

\/ matches the character / literally