Convert date data from a 2d array into a formatted string of dates using hyphenation to represent consecutive date ranges

I have an array like:

array(
    ['march'] => array(
        '2', '3', '4', '5', '6', '23', '24', '25', '30'
    );
);

I need to convert that into:

03/02/2012 - 03/06/2012
03/23/2012 - 03/25/2012
03/30/2012

You can find the consecutive timespans by looping through your array like so:

    $months = array(
        'march' => array(
            '2', '3', '4', '5', '6', '23', '24', '25', '30'
        )
    );

    $current_day = 0;
    $span_start = 0;
    $span_end = 0;

    foreach($months['march'] as $day) {

      if ($day > ++$current_day) {
        $current_day = $day;

        if ($span_start) {
          // print it out:
          echo "$span_start..$span_end\n";
        }

        $span_start = $day;
      }

      $span_end = $day;

    }

    // print the last one:
    echo "$span_start..$span_end";

Output: (Demo)

2..6
23..25
30..30

For formatting/parsing/printing the dates, however, others' suggestion to use the built in time and date functions are absolutely correct.