我想使用 data.tablesetkey
具有预定义列表id
and categories
,但收到错误消息:
> setkey(tr_id_cat_dt, id, categories)
Error in setkeyv(x, cols, verbose = verbose) :
some columns are not in the data.table: categories
我想要的所有元素id
and categories
显示为键。
这可能吗?
id 和category 是值列表,例如:
categories = c(9115L, 9909L, 3203L, 5558L, 4401L, 1703L, 1726L, 3504L, 3509L,
5122L, 5616L, 5619L, 2202L, 2119L, 6202L, 5824L, 799L, 4517L,
7205L, 706L)
dput(head(tr_id_cat_dt))
structure(list(id = c(86246, 86246, 86246, 86246, 86246, 86246
), category = c(706L, 706L, 706L, 706L, 706L, 706L)), .Names = c("id",
"category"), sorted = c("id", "category"), class = c("data.table",
"data.frame"), row.names = c(NA, -6L), .internal.selfref = <pointer: 0x015424a0>)