[R] Multidimensional contingency tables

[Giovanni Petris]

It seems to me that a combination of ftable and xtabs works fine:

> prob1<- data.frame(victim=c(rep('white',4),rep('black',4)),
+ perp=c(rep('white',2),rep('black',2),rep('white',2),rep('black',2)),
+ death=rep(c('yes','no'),4), count=c(19,132,11,52,0,9,6,97))
> prob1
  victim  perp death count
1  white white   yes    19
2  white white    no   132
3  white black   yes    11
4  white black    no    52
5  black white   yes     0
6  black white    no     9
7  black black   yes     6
8  black black    no    97
> ftable(xtabs(count ~ victim + perp + death, data = prob1))
             death  no yes
victim perp               
black  black        97   6
       white         9   0
white  black        52  11
       white       132  19
 
Best,
Giovanni

> Date: Tue, 22 Apr 2008 08:24:36 -0500
> From: hadley wickham <h.wickham at gmail.com>
> Sender: r-help-bounces at r-project.org
> Cc: R-help at stat.math.ethz.ch
> Precedence: list
> 
> On Mon, Apr 21, 2008 at 9:46 PM, Robert A. LaBudde <ral at lcfltd.com> wrote:
> > How does one ideally handle and display multidimenstional contingency
> >  tables in R v. 2.6.2?
> >
> >  E.g.:
> >
> >   > prob1<- data.frame(victim=c(rep('white',4),rep('black',4)),
> >  +   perp=c(rep('white',2),rep('black',2),rep('white',2),rep('black',2)),
> >  +   death=rep(c('yes','no'),4), count=c(19,132,11,52,0,9,6,97))
> >   > prob1
> >    victim  perp death count
> >  1  white white   yes    19
> >  2  white white    no   132
> >  3  white black   yes    11
> >  4  white black    no    52
> >  5  black white   yes     0
> >  6  black white    no     9
> >  7  black black   yes     6
> >  8  black black    no    97
> >
> >  The xtabs() function doesn't seem appropriate, as it has no means of
> >  using 'count'.
> >
> >  This must be a common problem.
> 
> You can also use the reshape package (http://had.co.nz/reshape)
> 
> cast(prob1, victim ~ perp, sum, value="count")
> cast(prob1, victim ~ perp ~ death, sum, value="count")
> cast(prob1, death + victim ~ perp, sum, value="count")
> 
> etc.
> 
> Hadley
> -- 
> http://had.co.nz/
> 
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> 

-- 

Giovanni Petris  <GPetris at uark.edu>
Associate Professor
Department of Mathematical Sciences
University of Arkansas - Fayetteville, AR 72701
Ph: (479) 575-6324, 575-8630 (fax)
http://definetti.uark.edu/~gpetris/