# NOT RUN {
df = data.frame(x = c(1, 2, 3, 4),
y = c(5, 6, 7, 8),
choice = c("x", "y", "x", "z"),
stringsAsFactors = FALSE)
make_dt_lookup_by_column("choice", "derived")(df)
# # base-R implementation
# df %.>% lookup_by_column(., "choice", "derived")
# # # data.table implementation (requies rquery 1.1.0, or newer)
# # df %.>% lookup_by_column(., "choice", "derived",
# # f_dt_factory = rqdatatable::make_dt_lookup_by_column)
# }
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