[datatable-help] Over-writing factors

[Damian Betebenner]

Not sure whether the following is an intended behavior with data.table. Perhaps it is something idiosyncratic with factors.
It is different than what one gets with data.frame

test.df <- data.frame(X=letters[1:10], Y=rnorm(10))
test.dt <- data.table(X=letters[1:10], Y=rnorm(10))

test.df$X <- "Something Different"
test.dt$X <- "Something Different"
Error in `[<-.data.table`(x, j = name, value = value) :
  Some or all RHS not present in factor column levels


test.df <- data.frame(X=letters[1:10], Y=rnorm(10))
test.dt <- data.table(X=letters[1:10], Y=rnorm(10))

test.df[["X"]] <- "Something Different"
test.dt[["X"]] <- "Something Different"




Damian Betebenner
Center for Assessment
PO Box 351
Dover, NH   03821-0351

Phone (office): (603) 516-7900
Phone (cell): (857) 234-2474
Fax: (603) 516-7910

dbetebenner at nciea.org<mailto:dbetebenner at nciea.org>
www.nciea.org<http://www.nciea.org/>



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