Nested Task error: Bad window span - what?

Specific Domains Data
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5

try this way (I don’t know if simple and efficient)

the scheme used here


using ShiftedArrays, DataFrames,RollingFunctions, Query


bigDf = DataFrame(i = 1:100, Growth = rand(100), Categories = rand(["a", "b", "c", "d", "f", "g"], 100))

TimedDfTest = @linq bigDf |>
         groupby(:Categories) |>
         transform(Trailing = running(prod, (:Growth .+1), 3).-1)


runshp(arr, sh) =cumprod(arr)./ShiftedArray(cumprod(arr),sh,default=1)
       
withOnlySA=transform(groupby(bigDf, :Categories),:Growth => (x -> runshp(x.+1, 3).-1) => :Trailing)

considera che


julia> withOnlySA.Trailing ≈   TimedDfTest.Trailing
true

julia> runshp([1,2,3,4],5)
4-element Vector{Float64}:
  1.0
  2.0
  6.0
 24.0