I'm running R 2.9.1 on winXP, using the library plyr.
Can anyone explain to me what is going wrong in this code? (in particular
see lines marked with ******************) Trying to modify objects in a list
created using dlply seems to corrupt the objects in the list.
> library(plyr)
> d=as.data.frame(cbind(c(1,1,1,2,2,2),c(1,2,3,4,5,6)))
> d
V1 V2
1 1 1
2 1 2
3 1 3
4 2 4
5 2 5
6 2 6
> c=dlply(d,.(V1))
> c
[[1]]
V1 V2
1 1 1
2 1 2
3 1 3
[[2]]
V1 V2
4 2 4
5 2 5
6 2 6
## display an element from the second data frame
> c[[2]][2,2]
[1] 5
## change element in the second data from
> c[[2]][2,2]=10
> c
[[1]]
V1 V2
2 1 2 **************
2.1 1 2 ************** What happened to V2?
2.2 1 2 **************
[[2]]
V1 V2
4 2 4
NA NA NA **********************************
6 2 6
##Try again with first data frame
> c=dlply(d,.(V1))
> c[[1]][2,2]=10 **********************************
> c
[[1]]
NULL ********************************* YIKES!
##Try again but copy c into a new list k
> c=dlply(d,.(V1))
> k=list(c[[1]],c[[2]])
> k[[1]]
V1 V2
1 1 1
2 1 2
3 1 3
> k[[2]][2,2]=10
> k
[[1]]
V1 V2
1 1 1
2 1 2
3 1 3
[[2]]
V1 V2
4 2 4
5 2 10 ***************************
6 2 6
> k[[1]][2,2]=10
> k
[[1]]
V1 V2
1 1 1
2 1 10 *******************************
3 1 3
[[2]]
V1 V2
4 2 4
5 2 10
6 2 6
[[alternative HTML version deleted]]
______________________________________________
R-help@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.
