r - How can I make a method to acces a data.table in a structure? -


suppose have this:

dt <- data.table(x = 1:10, y = 1:2) s <- structure(list(dt = dt), class = 'dt_test')

i want define [ function objects of class dt_test pass on arguments dt. example want able things like

s[, sum(x), = y] s[, z := x + y]

where [ applied dt. how can make happen?

it can done, i'm not sure should done though. defining method [ sends arguments down data.table pretty straight forward:

`[.dt_test` <- function(x, ...){   x[[1]][...] }  s[, sum(x), = y]

you have similar generics want supported, example want define [[.

i rather recommend referring data.table inside list directly, majo suggested in comment question. way it's easier understand whats happening in code else might reading (e.g. future you).


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