diff --git a/man/data.table.Rd b/man/data.table.Rd index 5ab586697..13d790f08 100644 --- a/man/data.table.Rd +++ b/man/data.table.Rd @@ -404,11 +404,6 @@ print(DT["b", v2:=84L, on="x"]) # subassign to new column by reference (NA DT[, m:=mean(v), by=x][] # add new column by reference by group # NB: postfix [] is shortcut to print() -# Injecting function into env parameter -DT <- data.table(a = rep(1:2, each = 5), b = 1:10) - -DT[, .(f=f(b), gval=g(b)), by = a, env = list(f = "sum", g=mean), verbose=TRUE] - # advanced usage DT = data.table(x=rep(c("b","a","c"),each=3), v=c(1,1,1,2,2,1,1,2,2), y=c(1,3,6), a=1:9, b=9:1) @@ -424,6 +419,9 @@ DT[, list(MySum=sum(v), MyMax=max(v)), by=.(x, y\%\%2)] # by 2 expressions +DT[, .(f=f(a), m=g(a)), by=b, verbose=TRUE, + env=list(f="sum", g=mean, b="x")] # subtitution via env arg + DT[, .(a = .(a), b = .(b)), by=x] # list columns DT[, .(seq = min(a):max(b)), by=x] # j is not limited to just aggregations DT[, sum(v), by=x][V1<20] # compound query