[R] Simple table with frequency variable

G. Draisma g.draisma at erasmusmc.nl
Thu Aug 2 08:57:16 CEST 2007

```Thank you Jim,
Sorry, that I was not clear enough.
Each case has a frequency variable N.
so when tabulating combinations (i,j) they
should be weighted with weight N.

In this case I would like a command
table(i,j,N)
resulting in
j
i   1  2
1 11 12
2 21 22
...
5 51 52

And I was looking for a table command
that allows for a case weight variable.
Gerrit.

on 01-Aug-2007 22:38 jim holtman said the following:
> I am not exactly sure what you are asking for.  I am assuming that you
> want a vector that represent the combinations that are given
> combinations that are present:
>
>> N
>  [1] 11 22 31 42 51 12 21 32 41 52
>> table(i,j)
>    j
> i   1 2
>   1 1 1
>   2 1 1
>   3 1 1
>   4 1 1
>   5 1 1
>> z <- table(i,j)
>> which(z==1)
>  [1]  1  2  3  4  5  6  7  8  9 10
>> which(z==1,arr.ind=T)
>   row col
> 1   1   1
> 2   2   1
> 3   3   1
> 4   4   1
> 5   5   1
> 1   1   2
> 2   2   2
> 3   3   2
> 4   4   2
> 5   5   2
>> x <- which(z==1,arr.ind=T)
>> paste(rownames(z)[x[,'row']], colnames(z)[x[,'col']], sep='')
>  [1] "11" "21" "31" "41" "51" "12" "22" "32" "42" "52"
>
>
> On 8/1/07, G. Draisma <g.draisma at erasmusmc.nl> wrote:
>> Hallo,
>>
>> Im trying to find out how to tabulate frequencies
>> of factors when the data have a frequency variable.
>>
>> e,g:
>> i<-rep(1:5,2)
>> j<-rep(1:2,5)
>> N<-10*i+j
>>
>> table(i,j) gives a table of ones
>> as each combination occurs only once.
>> How does one get a table with the corresponding N's?
>>
>> Thanks!
>> Gerrit.
>>
>>
>> --
>> Gerrit Draisma
>> Department of Public Health
>> Erasmus MC, University Medical Center Rotterdam
>> Room AE-103
>> P.O. Box 2040 3000 CA  Rotterdam The Netherlands
>> Phone: +31 10 4087124 Fax: +31 10 4638474
>> http://mgzlx4.erasmusmc.nl/pwp/?gdraisma
>>
>> ______________________________________________
>> 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.
>>
>
>

--
Gerrit Draisma
Department of Public Health
Erasmus MC, University Medical Center Rotterdam
Room AE-103
P.O. Box 2040 3000 CA  Rotterdam The Netherlands
Phone: +31 10 4087124 Fax: +31 10 4638474
http://mgzlx4.erasmusmc.nl/pwp/?gdraisma

```