The index cannot be negative.

[Gandhi]

I have an problem (data doesn't flow). In Power Query there is 1 error table (or 2, but second one is because first).

Error is:
Expression.Error: The index cannot be negative.
Details:
Value=[List]
Index=-1

and when I go to Error, it is in step "fnGetHighestParent".

= (n as number) as number =>
let
PosOfParent = List.PositionOf( ListTeamID, n ),
ParID = ListParentID{PosOfParent}
in
if ParID = null then ListTeamID{PosOfParent} else @fnGetHighestParent(ListParentID{PosOfParent})

In Data View, there is no negative indexes. So I don't know what this error means. Does anyone has any ideas?

Thank in advance!
-G

[danextian · Accepted solution]

Hi @Gandhi 

List.PositionOf returns -1 if the value being searched cannot be found.  There is an optional argument in this function if this happens.  Please see this documentation: https://learn.microsoft.com/en-us/powerquery-m/list-positionof