[SOLVED] Calc Element : Time start 08:00 + 3 hours = 11:00 + Solution

[marcq]

Hi,

I have created a form in which I'm calculating an arrival time based on a Start Time and a Duration Field.

I have created the two following fields

1. Start Time -> dropdown -> values 08:00 | 08:30 | 09:00 etc.
2. Arrival time -> calc -> calculation 1 + 2

Calculation Field in Calc Element :

$start = {nep_booking___book_starttime};
$duration = 3; // 3 hours

$end = strtotime($start) + $duration * 60;
return date ('H:i', $end );

I'm missing something since no value is calculated.

I would appreciate some help.

Thanks in advance.

Cheers,

Marc

 

[cheesegrits]

First thing, you need quotes around the placeholder, otherwise the generated PHP after we substitute is not syntacically correct, like ...

$start = 8:30;

So it needs to be ...

$start = '{nep_booking___book_starttime}';

... so the generated code we eval is then ...

$start = '8:30';

Then the issue is correctly calculating the time. You can use strtotime and doing math, but the best way (and a good habit to get in to) is to use PHP's DateTime class for any ind of date calculations ...

$start = '{nep_booking___book_starttime}';
if (!empty($start)) {
   $end = new DateTime($start);
   return $end->modify("+3 hours")->format("H:s");
}
else {
   return "";
}

... should do it. Note that this will correctly handle crossing midnight, so 23:30 + 3 would be 02:30.

the DateTime class has all kinds of useful functions for calculating differences, modifying, formatting etc.

-- hugh

 

[marcq]

Hi Hugh,

Thanks a lot, it is working like a charm and thank you also for your didactical way of explaining !

I would like now to use a dropdown instead a predefined static value ? I tried this which is not working :

$start = '{nep_booking___book_starttime}'; // start time of rental
$duration = '{nep_booking___book_termrental}'; // chosen duration
if (!empty($start)) {
   $end = new DateTime($start);
   return $end->modify(+$duration)->format("H:i");
}
else {
   return "";
}

Content of my databasejoin dropdown duration table :

id | duree
1 | 3 heures
2 | 5 heures
3 | 7 heures

 

[troester]

If you want to have the id use {nep_booking___book_termrental_raw}.

For debugging you can add e.g.
var_dump($start,$duration);
to see what you get.

 

[cheesegrits]

This is one of the few times where a simple dropdown might be more appropriate than a join. Simply set the value of the dropdown options to be the number of hours, and use the _raw placeholder, as suggested by Troester.

Using a join, you either have to then lookup the actual hour number from the table, or parse it out of the label with a regular expression ...

$matches = array();
if (preg_match('/^(\d+)\s+/', '{nep_booking___book_termrental}', $matches)) {
   $duration = $matches[1];
   // rest of the code ...
}

Whereas with a dropdown where the value is set to the duration, it's just ...

$duration = '{nep_booking___book_termrental_raw}';

-- hugh[/code]

 

[marcq]

Thank you troester and Hugh,

Sorry to bother you with this certainly trivial issue, I tried it with a join, but I get no result :

$start = '{fab_booking___book_starttime}';
$matches = array();
if (preg_match('/^(\d+)\s+/', '{fab_booking___book_termrental}', $matches)) {
   $duration = $matches[1];
if (!empty($start)) {
   $end = new DateTime($start);
   return $end->modify(+$duration)->format("H:i");
}
else {
   return "";
}
}

 

[cheesegrits]

Have you tried var_dump() to see what the placeholders are set to?



Sent from my Nexus 7 using Tapatalk

 

[marcq]

Hi Hugh,

Values returned for $duration with var_dump in the calc field are : "7" if i chose "7 heures", "5" if I chose "5 heures" etc. in the fab_booking___book_termrental dropdown.

Values returned for $matches with var_dump are : "array(2) { [0]=> string(2) "3 " [1]=> string(1) "3" }" if I chose "3 heures", "array(2) { [0]=> string(2) "5 " [1]=> string(1) "5" }" if I chose "5 heures" etc.

 

[cheesegrits]

I think the modifier still has to be a string ...

return $end->modify("+" . $duration . " hours")->format("H:i");

-- hugh

 

[marcq]

Thank you Hugh, I understand now how it works !

Solution from Hugh is :

$start = '{fab_booking___book_starttime}';
$matches = array();
if  (preg_match('/^(\d+)\s+/', '{fab_booking___book_termrental}', $matches)) {
    $duration = $matches[1];
   
if  (!empty($start)) {
    $end = new DateTime($start);
    return $end->modify("+" . $duration . " hours")->format("H:i");
}
else {
   return "";
}
}