Counter in a ForAll

[firektl]

Hello Community,

My question is the following:

I have a collection where I keep the attendance of the students.

This collection is uploaded to a gallery.

For items in the gallery, I create a temporary collection with the attendance of a student.

My collection is called colTemporal and it has this data:

Attendance | LessonDate

   Present       2 November 2020.
   Absent        6 November 2020.
   Absent        13 November 2020.
   Absent        09 January  2021.

I need to evaluate when the attendance is absent as long as it is consecutive, that is, the assists from 

6 November 2020

13 November 2020

09 January  2021

According to my logic, I only have to go through the collection and for each iteration ask if the assistance is ABSENT, when this condition is met, I need a way to create a counter, if the condition is false, I have to initialize that counter, well the attendance cycle is broken as ABSENT.

The problem is that when trying to create a set inside the ForAll it sends an error, it is not allowed.

[RandyHayes]

@firektl 

ForAll is not really a For Loop like you might be thinking.  It is often used that way, but overused for such.

It is intended to iterate through a series of records in a Table and to RETURN a table of records.

What you appear to be wanting to do is count the conditions where the Attendance is Absent.

In this case I would lean toward the CountRows for this:

CountRows(yourCollection, Attendance="Absent")

If this is not what you are looking for, then clarify please - perhaps share your current formula you are having issues with.

I hope this is helpful for you.

[firektl]

Hi @RandyHayes 

Thank you very much for your answer.

I will explain the scenario with an example.

A course has 6 classes (6 meetings that I must attend)

Class 1 of the course is 10/10/2020

Class 2 of the course is on 10/14/2020

Class 3 of the course is 10/17/2020

Class 4 of the course is on 10/19/2020

Class 5 of the course is 10/21/2020

Class 6 of the course is 10/25/2020

If a student has ABSENT attendance in classes 1, 2 and 3 I must count it, but if he has ABSENT attendance in classes 1, 4, 6 I do not count it, since having ABSENT attendance in a CONSECUTIVE way is an indicator that I must evaluate.

In my collection I have the attendance list ordered by date, so I try to cycle to ask for attendance.

I hope I have explained myself well.

Clear(colTemporal);;
ForAll(
    Filter(collectAttendanceStudent; StudentEmailId = ThisItem.StudentEmailId);
    Collect(
        colTemporal;
        {
            LessonDate: LessonDate;
            Attendance: Attendance;
            Estatus: Estatus
        }
    )
);;

ClearCollect(colTemporal; SortByColumns(colTemporal;"LessonDate"));;

ForAll(
    colTemporal;
    If(ThisRecord.Attendance = "Absent"
    ;
        Notify("Absent") // count++
    ;
        Notify("Present") // count = 0
    )
);;

[RandyHayes · Accepted solution]

@firektl 

Thanks for the explanation. Much clearer.

So here is a solution for you set a label in your Gallery and set the Text property to the following:

With({attendance:Filter(collectAttendanceStudent; StudentEmailId=ThisItem.StudentEmailId)},
    Sum(
        ForAll(Sequence(CountRows(attendance)), 
            With({thisRec:Last(FirstN(attendance, Value)).Estatus,
                  preStat:Coalesce(Last(FirstN(attendance, Value-1)).Estatus, "")}, 
                If(thisRec="Absent" && preStat="Absent", 1, 0)
            )
        ), 
        Value
    ) > 0
)

The label will show true if there is any consecutive absent markings and false if not.

i.e.  If a student has ABSENT attendance in classes 1, 2 and 3 - it will show true.

       If ABSENT attendance in classes 1, 4, 6 - it will show false

You can use that formula in whatever you need.

[firektl]

Hi @RandyHayes 

 With(  {attendance:Filter(collectAttendanceStudent; StudentEmailId=ThisItem.StudentEmailId)};
    Sum(
        ForAll(  Sequence(  CountRows(attendance)); 

            With(  { thisRec:Last(FirstN(attendance; Value)).Attendance;

                     preStat:Coalesce(Last(FirstN(attendance; Value-1)).Attendance ; "") }; 

                If( thisRec="Absent" && preStat="Absent"; 1; 0)
            )
        ); 
        Value
    ) >= 3
)

Make a change for it to work.

Thank you very much, it is possible that you can help me with another problem, I raised it.

Really very grateful! You are a sun

[RandyHayes]

@firektl 

Sorry I forgot to convert to semicolons for your language.

Glad it worked - pretty simple formula eh?  😁

Let me know what other problem you posted and I can take a look.

[firektl]

@RandyHayes 

It's another level, I'm just starting out and I don't know much about the functions and how to combine them. In fact, your solution is not 100% complete, but it helped me a lot.

And yes, I am from Venezuela and if you don't understand what I write it is for the translator, sorry for that.

I raised the other problem in the community but there was no solution, I'll leave you the url

Gallery with date columns 

Thank you very much, again!

[RandyHayes]

@firektl 

No worries.  Happy to help. 

I have brought your other post up and will review it to see what I can offer.  I'm ending the day here, so it will most likely be sometime over the weekend.