filtering a dataframe with a vector of rownames

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20110114/b3c9a913/attachment.pl>
Jonathan -
    To make your approach work, you'd need to replace ==
with %in%:
rows.to.keep<-which(rownames(data) %in% names.to.keep)
[1] 1 3 4

But to answer you're original question, remember that the
point of rownames is that they can be used to index a 
data frame:
data[rows.to.keep,]
[,1] [,2]
a    1    2
c    3    4
d    4    5

 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu

Hello,

Here's my problem. I have a large data frame and a vector with some of its row names. I'd like to have a new data frame only with those rows that match this vector of row names.

I tried this:

data<-cbind(c(1,2,3,4,5,6),c(2,3,4,5,6,7))
rownames(data)<-c("a", "b", "c","d","e","f")
names.to.keep<-c("a", "c", "d")
rows.to.keep<-which(rownames(data)==names.to.keep)

But it didn't work. Any suggestions?

thanks a lot.

Jonathan.

	[[alternative HTML version deleted]]

______________________________________________
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.

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20110114/6f1a2304/attachment.pl>

Hello,

Here's my problem. I have a large data frame and a vector with some of its row names. I'd like to have a new data frame only with those rows that match this vector of row names.

I tried this:

data<-cbind(c(1,2,3,4,5,6),c(2,3,4,5,6,7))
rownames(data)<-c("a", "b", "c","d","e","f")
names.to.keep<-c("a", "c", "d")
rows.to.keep<-which(rownames(data)==names.to.keep)
replace the last line by

  rows.to.keep <- data[names.to.keep,]

and please read the docs on indexing.

Best,
Uwe Ligges
But it didn't work. Any suggestions?

thanks a lot.

Jonathan.

	[[alternative HTML version deleted]]

______________________________________________
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.
An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20110114/e1be8476/attachment.pl>