# [R] classification tables

Gabor Grothendieck ggrothendieck at gmail.com
Mon Aug 7 13:04:21 CEST 2006

Also check out CrossTable in the gmodels package.

Regarding your other question, assuming we have
tab<-table(x,y) as in Philippe's post, the fraction of
pairs in x and y that match can be calculated via
any of these:

sum(x==y) / length(x)

sum(diag(tab)) / sum(tab)

library(e1071)
classAgreement(tab) # tab from above

sum(diag(prop.table(tab)))

On 8/7/06, Philippe Grosjean <phgrosjean at sciviews.org> wrote:
>
>  > x <- c(1,2,3,4,2,3,3,1,2,3)
>  > y <- c(2,1,3,4,1,3,3,2,2,3)
>  > table(x, y)
>    y
> x   1 2 3 4
>   1 0 2 0 0
>   2 2 1 0 0
>   3 0 0 4 0
>   4 0 0 0 1
>  > ?table
>
> Best,
>
> Philippe Grosjean
>
> ..............................................<°}))><........
>  ) ) ) ) )
> ( ( ( ( (    Prof. Philippe Grosjean
>  ) ) ) ) )
> ( ( ( ( (    Numerical Ecology of Aquatic Systems
>  ) ) ) ) )   Mons-Hainaut University, Belgium
> ( ( ( ( (
> ..............................................................
>
> Taka Matzmoto wrote:
> > Dear R-users
> >
> > I have two vectors. One vector includes true values and the other vector has
> > estimated values. Values are all integers from 1 to 4.
> >
> > For example,
> >
> > x <- c(1,2,3,4,2,3,3,1,2,3)
> > y <- c(2,1,3,4,1,3,3,2,2,3)
> >
> > I would like to a classfication table x by y. With the table, I would like
> > to calculate what percentage is correct classfication.
> >
> > Which R function do I need to use for creating a 4 * 4 classification table?
> >
> > Thank you.
> >
> > Taka,
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > and provide commented, minimal, self-contained, reproducible code.
> >
> >
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help