[R] frequency table for a list matching some conditions

[Dimitris Rizopoulos]

one way is the following:

mylist <- list(x1 = c("A","A","A","B","C","Z","Y"),
     x2 = c("D","D","E","E","F","Z","X"),
     x3 = c("A","A","A","B","Y","Z"))
newlist <- c("A","B","C","D","E","F")


tab <- t(sapply(mylist, function (x)
     table(factor(x, levels = newlist))))
tab[tab == 0] <- NA
tab


I hope it helps.

Best,
Dimitris


On 8/26/2010 11:47 AM, Olga Lyashevska wrote:
> Dear all,
>
> I have a list that contains 3 sublists( x1, x2, x3)
>
> mylist<-list(x1=c("A","A","A","B","C","Z","Y"),x2=c("D","D","E","E","F","Z","X"),x3=c("A","A","A","B","Y","Z"))
> mylist
> $x1
> [1] "A" "A" "A" "B" "C" "Z" "Y"
>
> $x2
> [1] "D" "D" "E" "E" "F" "Z" "X"
>
> $x3
> [1] "A" "A" "A" "B" "Y" "Z"
>
> I also have another list, that contains some specific elements.
> newlist<-c("A","B","C","D","E","F")
> newlist
> [1] "A" "B" "C" "D" "E" "F"
>
> I want to match mylist[1], mylist[2], etc with newlist and I am looking for the following output:
>
> 	A  B  C  D  E  F
> x1	3  1  1  NA NA NA
> x2	NA NA NA 2  2  1
> x3	3  1  NA NA NA NA
>
> Any thoughts?
>
> Many thanks
> Olga
>
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-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

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