Repeat steps multiple times over the same table

Hi donpep0,

You can try something like this:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WstT1SsxT0lEyBGFDAwOlWB2QoFtqElDACCxoaQoV9E0sAgoYgwSNLaFijgUgMROQmIGhMVxhJVDAFIjNLGAmepWCrDEDYTNjuFgOkG8OxDDTStOBHAuEQHBqAZBjCRaIBQA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Index = _t, Volume = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Date", type date}, {"Index", Int64.Type}, {"Volume", Int64.Type}}),
    Calculate = List.Accumulate(Table.ToRecords(#"Changed Type"), {[lst = {}]}, (a, n)=> 
        let 
        last = List.Last(a)[lst],
        updateVolume = if n[Volume] = null then Record.TransformFields(n, {"Volume", each List.Average(last)}) else n,
        updateLst = if List.Count(last) = 4 then List.Skip(last) else last,
        addLst = Record.AddField(updateVolume, "lst", updateLst & {updateVolume[Volume]})
        in a & {addLst}),
    Output = Table.FromRecords(List.Skip(Calculate), Value.Type(#"Changed Type"))
in
    Output

Kind regards,

John