$re = '/(\.\d\d[1-9]?)\d*/m';
$str = '3.820
11.325
60.100
441.005
11.23028741
1007.3335471
';
$subst = "$1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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