Split time by day of the week with an interval defined by two Zend_Date

I have two Zend_Date that represent an interval :

$start = new Zend_Date($punch->getStart());
$end = new Zend_Date($punch->getEnd());

$nbHours = $start->sub($end , Zend_Date::HOUR);
$nbMinutes = $start->sub($end , Zend_Date::MINUTE);

$hoursTotal = $nbHours->get(Zend_Date::HOUR);
$minutesTotal = $nbMinutes->get(Zend_Date::MINUTE);

Is there an simple way to split the interval by day of the week with Zend_Date when the interval > 24 hours?

For example, if I have an interval from Monday 8am to Tuesday 4:30pm, I would like to have an array containing monday = 16h and tuesday = 16:30.

You don't need to use Zend_Date for this, in fact it is probably better not to. You should use the date/time classes in PHP instead.

If I understand your question correctly you want an array of days and the hours worked for those days.

I first created a mock class to reflect your code example, I have assumed it is returning timestamps:-

class Punch
{
    public function getStart()
    {
        return time();
    }

    public function getEnd()
    {
        return strtotime('+36 hours 45 minutes');
    }
}

Then we set up the DateTime objects-

$Punch = new Punch();
$start = new DateTime();
$start->setTimestamp($Punch->getStart());
$end = new DateTime();
$end->setTimestamp($Punch->getEnd());

Then we use a DateInterval object to generate our iterable DatePeriod:-

$interval = new DateInterval('PT1M');
$minutes = new DatePeriod($start, $interval, $end);

Then we simply iterate over it counting the minutes worked in each day:-

$format = 'l';
foreach($minutes as $minute){
    if(!isset($result[$minute->format($format)])) $result[$minute->format($format)] = 0;
    $result[$minute->format($format)]++;
}

See the manual page for acceptable formats.

We now have the number of minutes worked in each day, converting them to hours is trivial:-

foreach($result as $key => $r){
    $result[$key] = $r/60;
}
var_dump($result);

Output (Obviously, you will get a different result running it at a different time) :-

array
  'Monday' => float 17.483333333333
  'Tuesday' => float 19.266666666667

So on Monday 17.48 hours were worked and 19.27 on Tuesday.

Alternatively:-

foreach($result as $key => $r){
    $result[$key] = floor($r/60) . ':' . $r % 60;
}

Would give the following output if that is closer to what you want:-

array
  'Monday' => string "17:29"
  'Tuesday' => string "19:16"

That's the simplest way I can think of doing it.