Saving plots in a data.table list column

Question

When I run...

library(data.table)
DT = CJ(id = 1, id2 = 1:3)[, .(
    d = as.IDate(\"2017-01-01\")+1:10, v = id*10 + id2*1:10
), by=.(id, id2)]

plotDT = DT[         


        

Answer 1

One working hack is to write j like

with(copy(.SD), {yada yada})

or similar, which ensures that references are to the per-group copy of .SD and don't get conflated.