$re = '/xmin = (\S+)\s+xmax = (\S+)\s+text = "([^"]*)/';
$str = 'intervals [1]:
xmin = 0
xmax = 13.139997023062838
text = ""
intervals [2]:
xmin = 13.139997023062838
xmax = 14.763036269953904
text = "Cities are like siblings in a large polygamous family."
intervals [3]:
xmin = 14.763036269953904
xmax = 17.01
text = ""';
preg_match_all($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