Question

I need to extract the date out of a string variable, and the date are formatted in various kind of formats as below:

$date1 = "03/12/2011 (Sat)";
$date2 = "3.12.2011 SAT";
$date3 = "Date: 03/12/2011 "; /* <-- the extra trailing space is intentional */
$date4 = "date:03/12/2011";
$date5 = "date: 03/12/2011";
$date6 = "03/12/2011";
$date7 = "13.12.2011 TUE";

What is the best way to create a PHP function which will work for all the input variables above in extracting the correct date info?

Answer 1

For more info on the DateTime object returned by the function, check the PHP documentation for the DateTime class.

/**
 * Parses date from string
 * @param string $str Uncorrected date string
 * @return DateTime PHP datetime object
 */
function date_grab($str)
{
  // regex pattern will match any date formatted dd-mm-yyy or d-mm-yyyy with
  // separators: periods, slahes, dashes
  $p = '{.*?(\d\d?)[\\/\.\-]([\d]{2})[\\/\.\-]([\d]{4}).*}';
  $date = preg_replace($p, '$3-$2-$1', $str);
  return new \DateTime($date);
}

// verify that it works correctly for your values:
$arr = array(
  "03/12/2011 (Sat)",
  "3.12.2011 SAT",
  "Date: 03/12/2011 ", /* <-- the extra trailing space is intentional */
  "date:03/12/2011",
  "date: 03/12/2011",
  "03/12/2011"
);

foreach ($arr as $str) {
  $date = date_grab($str);
  echo $date->format('Y-m-d') . "\n";
}