[R] count combined occurrences of categories

[David Winsemius]

On Jan 11, 2013, at 9:47 AM, arun wrote:

> HI David,
>
> I get different results with dcast()
>
> library(reshape2)
>   dcast(melt(tutu,"nam"),nam~value,length)
> #  nam art deb joy mar seb lio nem tat
> #1  da   2   3   1   4   1   1   0   0
> #2  fr   2   2   2   3   0   1   1   1
> #3  ya   1   2   1   0   0   1   1   0
>
>  tutus <- data.frame(nam=tutu$nam, au=with(tutu, c(au1,au2,au3)))
>  with(tutus,table(nam,au))
> #    au
> #nam  1 2 3 4 5 6 7
>  # da 2 3 1 2 4 0 0   #some numbers don't match the previous result
>   #fr 2 2 2 2 2 1 1
>   #ya 1 2 1 1 0 1 0
> #If I convert to as.character(), it matched with the dcast() results

Probably due to the fact I used c() on factors:

tutu <- data.frame(nam, au1, au2, au3, stringsAsFactors=FALSE)
 > tutus <- data.frame(nam=tutu$nam, au=with(tutu, c(au1,au2,au3)))
 > tutab <- with(tutus, table(nam, au)  )
 > tutab
     au
nam  art deb joy lio mar nem seb tat
   da   2   3   1   1   4   0   1   0
   fr   2   2   2   1   3   1   0   1
   ya   1   2   1   1   0   1   0   0

--  
David.
>
> tutunew<-data.frame(nam=tutu 
> $ 
> nam 
> ,au 
> =with(tutu,c(as.character(au1),as.character(au2),as.character(au3))))
> with(tutunew,table(nam,au))
> #    au
> #nam  art deb joy lio mar nem seb tat
>  # da   2   3   1   1   4   0   1   0
>   #fr   2   2   2   1   3   1   0   1
>   #ya   1   2   1   1   0   1   0   0
> A.K.
>
>
>
>
>
> ----- Original Message -----
> From: David Winsemius <dwinsemius at comcast.net>
> To: Biau David <djmbiau at yahoo.fr>
> Cc: r help list <r-help at r-project.org>
> Sent: Friday, January 11, 2013 12:20 PM
> Subject: Re: [R] count combined occurrences of categories
>
>
> On Jan 11, 2013, at 2:54 AM, Biau David wrote:
>
>> Dear all,
>>
>> i would like to count the number of times where I have combined  
>> occurrences of the categories of 2 variables.
>>
>> For instance, in the dataframe below, i would like to know how many  
>> times each author (au1, au2, au3 represent the first, second, third  
>> author) is associated with each of the category of the variable  
>> 'nam'. The position of the author does not matter.
>>
>> nam <- c('da', 'ya', 'da', 'da', 'fr', 'fr', 'fr', 'da', 'ya', 'fr')
>> au1 <- c('deb', 'art', 'deb', 'seb', 'deb', 'deb', 'mar', 'mar',  
>> 'joy', 'joy')
>> au2 <- c('art', 'deb', 'mar', 'deb', 'joy', 'mar', 'art', 'lio',  
>> 'nem', 'mar')
>> au3 <- c('mar', 'lio', 'joy', 'mar', 'art', 'lio', 'nem', 'art',  
>> 'deb', 'tat')
>> tutu <- data.frame(cbind(nam, au1, au2, au3))
>
> You should first abandon the practice of using `cbind` inside  
> `data.frame`. Obscure errors will plague your R experience until you  
> do so.
>
> Bas solution:
>
>> tutus <- data.frame(nam=tutu$nam, au=with(tutu, c(au1,au2,au3)))
>> tutab <- with(tutus, table(nam, au)  )
>> tutab
>     au
> nam  1 2 3 4 5 6 7
>   da 2 3 1 2 4 0 0
>   fr 2 2 2 2 2 1 1
>   ya 1 2 1 1 0 1 0
>
> --
> David Winsemius, MD
> Alameda, CA, USA
>
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>

David Winsemius, MD
Alameda, CA, USA