Add Row Numbers to a Power Apps Collection

This article describes how to add sequential row numbers to a Power Apps collection.

Use the following formula to add sequential row numbers to any collection.

ForAll (
    colCollectionToBeNumbered,
    Collect(
        colTemp,
        Last(
            FirstN(
                AddColumns(
                    DropColumns(
                        colCollectionToBeNumbered,
                        "RowNumber"
                    ),
                    "RowNumber",
                    CountRows(colTemp) + 1
                ),
                CountRows(colTemp) + 1
            )
        )
    )
);
ClearCollect(colCollectionToBeNumbered,colTemp);
Clear(colTemp);

 Alternative method without using Add and Drop Columns which is a bit cleaner:

With(
    {
        records:colCollectionToBeNumbered
    },
    ForAll(
        Sequence(CountRows(records)),
        Patch(
            Last(
                FirstN(records,Value)),
                {rowNumber: Value}
            )
        )
)