Duplicate detection in collection

[vffdd]

I have a blank gallery to which I dynamically add rows however many I need and then add data to those rows.   On save I create a collection from that data and then I patch it back to a sharepoint list.     All works well.

However I now need the functionality to check for duplicates in one of the columns (it's text input, number type) before I patch it through to the sharepoint list. notify the user and give them a chance to update it..  (notify function would be absolutely fine for this)

I have read numerous duplicate questions, watch a ton of videos but can't quite get the scenario I need.

So somewhere between Collect(mycollection.....  and Patch (mycollection  I need an If duplicate then notify if not then patch !

Any ideas gratefully accepted

TIA

[CNT]

@vffdd Follow this example and replace mySPCollection with your collection name and Value with the name of your column.

ClearCollect(mySPCollection, ["1","2","2","3","4","4","5"]);
If(CountIf(AddColumns(GroupBy(mySPCollection,"Value", "myGroup"), "myCount", CountRows(myGroup)), myCount>1)>0, Notify("Duplicates Found"))

Please remember to give a 👍 and accept my solution as it will help others in the future.

[vffdd]

brilliant thanks @CNT   I'm almost there.. that worked but showed up another issue I have by making it work 🙂   The next command after the collection has been patched is to navigate to another screen and it's just another command separated by ; from the rest.  However IF there is a duplicate and patch doesn't happen I don't want to navigate?  because I want them to fix it.. I only want to navigate if the patch has taken place.. so how do I join the navigate to the end of the patch as opposed to it being a separate command?  I know if it was a form I could use an on success but don't think there anything similar in patch?   

[CNT · Accepted solution]

@vffdd Check this out,

ClearCollect(mySPCollection, ["1","2","2","3","4","4","5"]);
If(CountIf(AddColumns(GroupBy(mySPCollection,"Value", "myGroup"), "myCount", CountRows(myGroup)), myCount>1)>0, 
Notify("Duplicates Found"),
Patch(.......); Navigate(.....))

In this case Patch and Navigate will be executed ONLY if there are no duplicates!

Please remember to give a 👍 and accept my solution as it will help others in the future.

[vffdd]

Fantastic, thanks so much amazing what moving a bracket can do !!  🙂

[CNT]

@vffdd 

Glad to help!