[Rd] Private: Problem with tapply/lapply and sample (PR#3286)
peter.gedeck at pharma.novartis.com
peter.gedeck at pharma.novartis.com
Wed Jun 18 19:38:33 MEST 2003
Full_Name: Peter Gedeck
Version: R1.6.2 and R1.7.0
OS: Windows XP
Submission from: (NULL) (194.191.169.72)
Hello,
I marked the bug report Private, as I don't want my email address on the web
server. The problem that I found is best explained using an example.
index <- 1:6
cluster <- c(1,1,1,2,2,3)
tapply(index,cluster,sample)
gives
$"1"
[1] 2 1 3
$"2"
[1] 4 5
$"3"
[1] 3 2 4 1 6 5
The result for 1 and 2 is correct, the last line should however be
$"3"
[1] 6
and not return a sample containing all data. Other functions seem to work
correctly,
> tapply(index,cluster,min)
1 2 3
1 4 6
> tapply(index,cluster,max)
1 2 3
3 5 6
> tapply(index,cluster,sum)
1 2 3
6 9 6
Another example which maybe gives an indication where the problem lies is
> index <- 1:3
> cluster <- c(1,2,3)
> tapply(index,cluster,sample)
$"1"
[1] 1
$"2"
[1] 2 1
$"3"
[1] 1 3 2
The results should be 1, 2 and 3.
I tried to identify where the error occurs, but I think the error happens in
.Internal(lapply(X,FUN)) in lapply.
Regards,
Peter
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