# [R] How to include NA's of a factor in table?

Gabor Grothendieck ggrothendieck at gmail.com
Mon Jul 10 14:34:13 CEST 2006

```If we specify exclude=NULL in factor then it need not also be
specified in table:

fcv <- factor(c('a', NA, 'c'), exclude=NULL)
table(fcv)

On 7/10/06, Jacques VESLOT <jacques.veslot at good.ibl.fr> wrote:
> fcv <- factor(c('a', NA, 'c'), exclude=NULL)
> table(fcv, exclude=NULL)
> -------------------------------------------------------------------
> Jacques VESLOT
>
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> -------------------------------------------------------------------
>
>
> Heinz Tuechler a écrit :
> > Dear All,
> >
> > Is there a better way to include NA's of a factor in the output of table()
> > than using as.character()?
> > Admittedly, I do not understand the help page for table concerning the
> > exclude argument applied to factors. I tried in different ways, but could
> > not get NA to be included in the table, if not using as.character() (see
> > example).
> >
> > Greetings,
> > Heinz
> >
> > ## example
> > fcv <- factor(c('a', NA, 'c'))
> > table(fcv)                # shows a, c
> > table(fcv, exclude='a')   # shows c
> > table(fcv, exclude="")    # shows a, c
> > table(fcv, exclude=NULL)  # shows a, c
> > table(as.character(fcv), exclude=NULL) # shows a, c, NA
> >
> > platform       i386-pc-mingw32
> > arch           i386
> > os             mingw32
> > system         i386, mingw32
> > status         Patched
> > major          2
> > minor          3.1
> > year           2006
> > month          07
> > day            01
> > svn rev        38471
> > language       R
> > version.string Version 2.3.1 Patched (2006-07-01 r38471)
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help