Answer to: Calculate multilple stats for two or more columns in R data.table

An alternative where the function takes "all columns" (instead of individual columns). stats2 <- function(frm) { Map(function(x, nm) { list(max(x), min(x)) |> setNames(paste0(nm, c("_maximo", "_minimo"))) }, frm, names(frm)) |> unname() |> do.call(cbind.data.frame, args = _) } dt[, stats2(.SD), by = class, .SDcols = c('val1', 'val2')] # class val1_maximo val1_minimo val2_maximo val2_minimo # <char> <int> <int> <num> <num> # 1: a 9 1 120 30 # 2: b 11 2 90 10 # 3: c 12 4 110 50 Reproducible data: set.seed(42) dt <- data.table(class = rep(c('a', 'b', 'c'), 4), val1 = sample(12), val2 = sample(12)*10) If .-separated names is okay instead of _, you can simplify stats2 a bit with stats3 <- function(frm) { lapply(frm, function(x) list(maximo = max(x), minimo = min(x))) |> do.call(cbind.data.frame, args = _) } dt[, stats3(.SD), by = class, .SDcols = c('val1', 'val2')] # class val1.maximo val1.minimo val2.maximo val2.minimo # <char> <int> <int> <num> <num> # 1: a 9 1 120 30 # 2: b 11 2 90 10 # 3: c 12 4 110 50