[R] Avoid for-loop in creating data.frames

[Henrique Dallazuanna]

Try this:

lapply(1:ncol(set2), function(idx)set2[is.na(set2[,idx]),idx, drop = FALSE])

On Thu, Dec 10, 2009 at 2:33 PM, Andreas Wittmann
<andreas_wittmann at gmx.de> wrote:
> Hi babtiste,
>
> thank you very much for your fast answer. your solution is very good, but i
> also need the dimnames as in the for-loop for further calculations.
>
> best regards
>
> Andreas
>
>
>
>
> baptiste auguie wrote:
>>
>> Hi,
>>
>> Is the following close enough?
>>
>> apply(set2, 2, function(x) x[is.na(x)])
>>
>> HTH,
>>
>> baptiste
>>
>> 2009/12/10 Andreas Wittmann <andreas_wittmann at gmx.de>:
>>
>>>
>>> Dear R-users,
>>>
>>> after several tries with lapply and searching the mailing list, i want to
>>> ask, wheter and how it is possibly to avoid the for-loop in the following
>>> piece of code?
>>>
>>> set2<-as.data.frame(matrix(rnorm(9),ncol=3))
>>>
>>> set2[1,1] <- NA
>>> set2[3,2] <- NA
>>> set2[2,1] <- NA
>>>
>>> dimnames(set2)[1] <- list(c("A","B","C"))
>>>
>>> r <- !is.na(set2)
>>> imp <- vector("list", ncol(set2))
>>>
>>> for (j in 1:dim(set2)[2])
>>> {
>>>  imp[[j]] <- as.data.frame(matrix(NA, nrow = sum(!r[,j]), ncol = 1))
>>>  dimnames(imp[[j]]) <- list(row.names(set2)[r[,j] == FALSE], 1)
>>> }
>>>
>>>
>>> many thanks and best regards
>>>
>>> Andreas
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>
>>
>>
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O