Hi,
I am confused by results from:
> ddply(aa, names(aa), colwise(sum))
I thought ddply was just calling colwise(sum)() with each column.
However ddply() returns a 13 x 5 result !!
The general result I expected is similar to that of apply() , or
using colwise(sum)() alone. Shouldn't ddply() produce the same ?
Thanks in advance for your help,
- Stuart Andrews
> set.seed(1234)
> aa = as.data.frame(matrix(rnorm(100)>0.3,nrow=20))
> names(aa) = c('a','b','c','d','e')
> head(aa)
a b c d e
1 FALSE FALSE FALSE TRUE TRUE
2 TRUE TRUE FALSE TRUE FALSE
3 TRUE TRUE FALSE TRUE TRUE
4 TRUE FALSE FALSE TRUE FALSE
5 TRUE FALSE FALSE TRUE FALSE
6 FALSE FALSE FALSE FALSE TRUE
> ddply(aa, names(aa), colwise(sum))
a b c d e
1 0 0 0 0 0
2 0 0 0 0 2
3 0 0 0 4 0
4 0 0 0 1 1
5 0 0 1 0 0
6 0 0 2 0 2
7 0 0 1 1 0
8 0 2 0 0 0
9 0 1 0 0 1
10 1 0 0 0 0
11 2 0 0 0 2
12 1 0 0 1 0
13 1 0 0 1 1
> apply(as.matrix(aa),2,sum)
a b c d e
5 3 4 8 9
> colwise(sum)(aa)
a b c d e
1 5 3 4 8 9
... Isn't ddply() just doing something like this for each column??
> colwise(sum)(aa[,1,drop=F])
a
1 5
______________________________________________
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.
