Hi,
Try:
row.names(res) <- gsub(".*\\.","",row.names(res))
row.names(res)[1:2]
#[1] "23" "2"
A.K.
Thank you very much.
But it's possible have the inicial number of the row without
a.23, but only 23, for example? It's important to know which row I had
select.
Thank you very much for your help.
On Tuesday, February 11, 2014 12:21 PM, arun <smartpink...@yahoo.com> wrote:
Hi,
Try:
set.seed(42)
dat <-as.data.frame(matrix(sample(20:100,4*45,replace=TRUE),ncol=4))
set.seed(345)
dat <- within(dat,class1 <- sample(letters[1:3],45,replace=TRUE) )
table(dat$class1)*0.4
#
# a b c
#6.0 4.8 7.2
set.seed(85)
res <- do.call(rbind,lapply(split(dat,dat$class1),function(x)
x[sample(nrow(x),round(0.4*nrow(x)),replace=FALSE),]))
table(res$class1)
#a b c
#6 5 7
row.names(res) <- 1:nrow(res)
res
A.K.
Hi,
I have now a new question. Suppose that we have the data frame
V1 V2 V3 V4 class
23 32 65 33 a
15 54 76 98 b
21 23 98 23 a
23 32 65 33 c
15 54 76 98 b
21 23 98 23 c
23 32 65 33 a
15 54 76 98 b
21 23 98 23 c
...
and I need to select 40% (for example) to each class (consider that we have a
lot of rows).
Thanks
______________________________________________
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.
