I also not find this in the source code, but you can rewrite the function
with this:
expand.grid <-
function (..., KEEP.OUT.ATTRS = TRUE, stringsAsFactors = FALSE)
{
nargs <- length(args <- list(...))
if (!nargs)
return(as.data.frame(list()))
if (nargs == 1L && is.list(a1 <- args[[1L]]))
nargs <- length(args <- a1)
if (nargs == 0L)
return(as.data.frame(list()))
cargs <- args
iArgs <- seq_len(nargs)
nmc <- paste("Var", iArgs, sep = "")
nm <- names(args)
if (is.null(nm))
nm <- nmc
else if (any(ng0 <- nzchar(nm)))
nmc[ng0] <- nm[ng0]
names(cargs) <- nmc
rep.fac <- 1L
d <- sapply(args, length)
if (KEEP.OUT.ATTRS) {
dn <- vector("list", nargs)
names(dn) <- nmc
}
orep <- prod(d)
if (orep == 0L) {
for (i in iArgs) cargs[[i]] <- args[[i]][FALSE]
}
else {
for (i in iArgs) {
x <- args[[i]]
if (KEEP.OUT.ATTRS)
dn[[i]] <- paste(nmc[i], "=", if (is.numeric(x))
format(x)
else x, sep = "")
nx <- length(x)
orep <- orep/nx
x <- x[rep.int(rep.int(seq_len(nx), rep.int(rep.fac,
nx)), orep)]
if(stringsAsFactors){
if (!is.factor(x) && is.character(x))
x <- factor(x, levels = unique(x))
}else{
x
}
cargs[[i]] <- x
rep.fac <- rep.fac * nx
}
}
if (KEEP.OUT.ATTRS)
attr(cargs, "out.attrs") <- list(dim = d, dimnames = dn)
rn <- .set_row_names(as.integer(prod(d)))
structure(cargs, class = "data.frame", row.names = rn)
}
On Thu, Jun 25, 2009 at 8:21 AM, Rainer M Krug <r.m.k...@gmail.com> wrote:
> Hi
>
> I have the feeling, that the argument stringsAsFactors has no impact in the
> function expand.grid:
>
> a <- c("PR", "NC", "A2", "BS")
> b <- c(1, 0.5, 0.25, 0.125, 0.0625, 0.03125)
>
> class(expand.grid(css, fscs, stringsAsFactors=FALSE)[[1]])
> [1] "factor"
> class(expand.grid(css, fscs, stringsAsFactors=TRUE)[[1]])
> [1] "factor"
>
> Also, when I look at the code of expand.grid, stringsAsFactors does not
> occur in the code.
>
> Am I missing something?
>
> > version
> _
> platform i486-pc-linux-gnu
> arch i486
> os linux-gnu
> system i486, linux-gnu
> status
> major 2
> minor 9.0
> year 2009
> month 04
> day 17
> svn rev 48333
> language R
> version.string R version 2.9.0 (2009-04-17)
>
> Cheers,
>
> Rainer
> --
> Rainer M. Krug, Centre of Excellence for Invasion Biology, Stellenbosch
> University, South Africa
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
[[alternative HTML version deleted]]
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