$re = '/(?:^|[(\s[])(\d+(?:[.,]0+(?!\d))?)(?=[]\s)]|$)/m';
$str = '2 2.0
Test (2.00001) Test (2.000) Test 2.1 Test (2,0001) Test 2,000 Test 2,1000 test 2';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($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