xtabs and NA
On Mon, Feb 9, 2015 at 8:52 AM, Kirill M?ller
<kirill.mueller at ivt.baug.ethz.ch> wrote:
Hi I haven't found a way to produce a tabulation from factor data with NA values using xtabs. Please find a minimal example below, it's also on R-pubs [1]. Tested with R 3.1.2 and R-devel r67720. It doesn't seem to be documented explicitly that it's not supported. From reading the code [2] it looks like the relevant call to table() doesn't set the "useNA" parameter, which I think is necessary to make NAs show up in the result. Am I missing anything? If this a bug -- would a patch be welcome? Do we need compatibility with the current behavior? I'm aware of workarounds, I just prefer xtabs() over table() for its interface.
Passing table the output of model.frame would still allow the use of a formula interface:
mf <- model.frame( ~ data, na.action = na.pass)
do.call("table", c(mf, useNA = "ifany"))
a b c <NA> 1 1 1 1
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