I have two datasets
ds = Dataset@*
Map[AssociationThread[{"ID", "Date", "A"} -> #] &]@{
{"C12", SQLDateTime[{2012, 12, 11, 0, 0, 0.}], 10},
{"C12", SQLDateTime[{2015, 2, 19, 19, 30, 0.}], 9},
{"C12", SQLDateTime[{2013, 1, 22, 0, 0, 0.}], 12},
{"C10", SQLDateTime[{2013, 1, 28, 9, 25, 0.}], 15},
{"C10", SQLDateTime[{2014, 3, 21, 20, 0, 0.}], 12},
{"C11", SQLDateTime[{2014, 8, 27, 6, 40, 0.}], 8}}
and
ds2 = Dataset@*
Map[AssociationThread[{"ID", "Date", "B"} -> #] &]@{
{"C10", SQLDateTime[{2013, 1, 28, 0, 25, 0.}], 315},
{"C11", SQLDateTime[{2013, 3, 2, 6, 40, 0.}], 128},
{"C12", SQLDateTime[{2012, 10, 10, 0, 0, 0.}], 10}}
and I combine it via
SortBy["ID"]@JoinAcross[dsds4=SortBy["ID"]@JoinAcross[ds, ds2, {"ID", "Date"}, "Outer"]
Now, I want to replace the unmatched B values with the last (according to date) occurring B value of the matching ID. Eg. in lines 2 and 3: 315 for B, in line 5: 128 and lines 7-9: 10.
The result should look like this:
I tried something like this, where I first replaced the Missing["Unmatched"]->0 and then
Module[{prev = #"B" &}, ds4[All, {If[#"B" == 0, <|#, "B" -> #"B" + prev|>, #],
prev = #"B"}[[1]] &]]
But it doesn't yield the desired result. It only replaces the first occurrence. Any ideas?
