[R] na.action in xtabs - how to include NAs?

[William Dunlap]

Try both na.action=na.pass and exclude=NULL, the first is for
xtabs' call to model.frame and the second for when it prepares
the data from model.frame's output for a call to table.

xtabs(formula = ~a + b, data = x, na.action = na.pass, exclude = NULL)
Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Wed, Sep 30, 2015 at 7:56 AM, Dimitri Liakhovitski
<dimitri.liakhovitski at gmail.com> wrote:
> Please help:
>
> # I have a data frame x:
> x <- data.frame(a = c(1:3, NA), b = c(NA, 2:4))
>
> # I run a cross-tab keeping NAs, like this:
> table(x[c("a", "b")], useNA = "ifany")
>
> # I want to reproduce it using xtabs, but it ignores NAs:
> xtabs(~ a + b, x)
>
> # I can't figure out how to force xtabs to include NAs.
> # All my attempts below fail to include NAs:
> xtabs(~ a + b, x, na.action(na.pass))
> xtabs(~ a + b, x, na.action = "na.pass")
> xtabs(~ a + b, x, na.action(na.pass(x)))
> xtabs(~ a + b, x, exclude = NULL)
>
> Thank you for your hints!
> --
> Dimitri Liakhovitski
>
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