[R] List of List in Data Frame

[David Winsemius]

On Jan 31, 2011, at 8:45 PM, Gundala Viswanath wrote:

> Dear sirs,
>
> I have a data that is generated like this:
>
>> dat1 <- data.frame(V1 = rep(1, 5), V2 = sample(c(40:45), 5))
>> dat2 <- data.frame(V1 = sample(c(0,1), 5, replace = TRUE), V2 =  
>> sample(c(40:45), 5, replace = TRUE))
>
> What I want to do is to obtain a data frame that contain list of list.
>
>> hiv
> $hiv.dat1
> $hiv.dat1$V1[[1]]
> [1] 1 1 1 1 1
>
> $hiv.dat1$V2[[1]]
> [1] 41 42 43 40 44
>
>
> $hiv.dat2
> $hiv.dat2$V1[[1]]
> [1] 0 1 1 0 0
>
> $hiv.dat2$V2[[1]]
> [1] 42 43 40 44 43
>
> But why this line of command failed to create that?
>
>> hiv <- list(hiv.dat1 = as.list(dat1), hiv.dat2 = as.list(dat2))
>
> Especially it gives  "$hiv.dat1$V1" instead of "$hiv.dat1$V1[[1]]".

But that _is_ a list of lists. Two lists, each with two sub-lists

  hiv$hiv.dat1$V1[[1]] is just the element "1". It is not a list.


>
> How can we correct that?
> I need this particular data structure required for a specific  
> package (ROCR).

To do what operation or procedure?

>

-- 

David Winsemius, MD
West Hartford, CT