How to run functions in sequence order in PowerApps?

[aaedla]

Hi,

I need suggestions to run functions in sequence. Is there anyway to run functions in a sequence order? To run concurrently, there is a concurrent function but I don't see anything for sequence.

I have a scenario where I need to run Delete, collection and patch for all in a sequence.

Any suggestions would be greatly appreciated.

[RandyHayes]

@aaedla 

If they are all in the same formula, then they will evaluate sequentially. 

i.e.

Delete(someList, someRecord/Table);
Collect(someCollection, someCriteria);
Patch(someList, someRecord/Table)

I hope this is helpful for you.

[aaedla]

Thank you for your comments. I have already tried and functions are not running in a sequence order. Is there any way to force the functions in a sequence order.

Delete function deletes records from database.

datacollection - collects the data from gallery

For All patch-adds data to databse.

[RandyHayes]

@aaedla 

How are you determining that they are not sequential?  

[aaedla]

Sometimes it's adding new records sometimes not. There is no issue with the code. I tried without delete function for number of times and I didn't get any issue with the collection and patch functions.

[RandyHayes]

@aaedla 

Well, it really depends on your Formulas.  But keep in mind that PowerApps is not a development platform, it is a platform that is modeled around Excel.  And, just like in Excel, when you change one cell that other cells are using in their formulas, everything will re-evaluate.  

So to is the case in PowerApps...So, if your Delete function is impacting a datasource that perhaps your Gallery is using, then as soon as that delete occurs, the Gallery will re-evaluate its Formulas and at that point might be different than what you expected.

Your best approach is to keep it simple.  Avoid collections unless you are creating an in-memory database.  Since you have a Gallery, you already have a table of records to use - you don't need another collection/table from it.

Or, if there is some reason you think you need a collection, then gather your collection first as it is a snapshot and will not change.  But then you have an in-memory duplicate of data and you will need to manage it as such.

However, to the initial question, the functions in your Formulas WILL evaluate sequentially.  However, if you have functions that impact controls or other formulas in it, those formulas will re-evaluate at the same time.  Think Excel...not C++

[shdfbasfgagfkay · Accepted solution]

I have come across this few times, even in cases where no gallery source was being modified, and I was thinking my coding was incorrect.

It is very painful especially when the claim (here: Understand behavior formulas for canvas apps - Power Apps | Microsoft Docs) is that it runs in certain sequence if defined using semicolons!

[GamerTuku]

You may have to use Timer control in some instances. I have varying results when running dependant functions. It is very frustrating. 

[Karluzo]

Timer control - this should be the accepted answer, thanks. That's crazy anyway, powerapps look like a bad clone of Scratch.

[Rodrigo_Fenix]

Great comment, Randy!
Helped me out a lot and made me rethink my app strategy.
In my case, I deleted some variables that were not being refreshed after I updated the collection, and instead used  functions. As soon I update the collection the functions result was also updated. In my case, the "think like Excel" helped.

PS: At first glance I thought your comment was useless, but right after facing the problem again it all made sense.
Thanks mate.