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run code in 300+ PHP versions simultaneously
<?php $string = "{random_one}[SUBSTRING1] blah [SUBSTRINGX] blah blah {random_two}[SUBSTRING2] blah blah blah{random_one}[SUBSTRING3]"; preg_match_all("/{.+?}\[(.+?)\]/i", $string, $matches); var_dump($matches[1]);

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34.3 ms | 405 KiB | 5 Q