$re = '/(?<agroup>\|a(?<title>.+)){0,1}(?<bgroup>\|b(?<subtitle>.+)){0,1}(?<cgroup>\|c(?<author_info>.+)){0,1}/u';
$str = '|a První kroky z deprese / |c Sue Atkinson ; [z angličtiny přeložil Jindřich Kotvrda]';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php