Dear All,
Probably a very basic question, but can't seem to work my way around it.
I want to which row has the maximum value. But what if the row names do not
correspond with the row numbers. In the example below, you'll see that the
max of example is row 4, but the name of row 4 is "9". How do I get R
to return "9" as value, instead of 4.
example <- matrix(c(0,0,0,1), 4, 1, dimnames=list(c("1",
"3", "5", "9"), c("1")))
which.max(example)
[1] 4
Hope someone can help out.
Gijs Schumacher, MSc
PhD candidate
--------------------------------------
Department of Political Science
VU University Amsterdam
Contact:
Tel: +31(0)20 5986798
Fax: +31(0)20 5986820
Web: http://home.fsw.vu.nl/g.schumacher
Email: g.schumacher@vu.nl<mailto:g.schumacher@fsw.vu.nl>
Visiting address:
Metropolitan
Buitenveldertselaan 2
Room Z - 333
Mail:
De Boelelaan 1081
1081 HV Amsterdam
The Netherlands
[[alternative HTML version deleted]]
Perhaps not the most elegant.
rownames(example)[which.max(example)]
If you wanted to type less, you could always write a function.
names.max <- function(x){
return(rownames(example)[which.max(example)])
}
-Mitch
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
Behalf Of Schumacher, G.
Sent: Monday, May 02, 2011 7:54 AM
To: 'r-help at r-project.org'
Subject: [R] how to get row name using the which function
Dear All,
Probably a very basic question, but can't seem to work my way around it.
I want to which row has the maximum value. But what if the row names do not
correspond with the row numbers. In the example below, you'll see that the
max of example is row 4, but the name of row 4 is "9". How do I get R
to
return "9" as value, instead of 4.
example <- matrix(c(0,0,0,1), 4, 1, dimnames=list(c("1",
"3", "5", "9"),
c("1")))
which.max(example)
[1] 4
Hope someone can help out.
Gijs Schumacher, MSc
PhD candidate
--------------------------------------
Department of Political Science
VU University Amsterdam
Contact:
Tel: +31(0)20 5986798
Fax: +31(0)20 5986820
Web: http://home.fsw.vu.nl/g.schumacher
Email: g.schumacher at vu.nl<mailto:g.schumacher at fsw.vu.nl>
Visiting address:
Metropolitan
Buitenveldertselaan 2
Room Z - 333
Mail:
De Boelelaan 1081
1081 HV Amsterdam
The Netherlands
[[alternative HTML version deleted]]
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
rownames(which(example == max(example), arr.ind=TRUE)) Uwe Ligges On 02.05.2011 13:54, Schumacher, G. wrote:> Dear All, > > Probably a very basic question, but can't seem to work my way around it. > > I want to which row has the maximum value. But what if the row names do not correspond with the row numbers. In the example below, you'll see that the max of example is row 4, but the name of row 4 is "9". How do I get R to return "9" as value, instead of 4. > > example<- matrix(c(0,0,0,1), 4, 1, dimnames=list(c("1", "3", "5", "9"), c("1"))) > which.max(example) > > [1] 4 > > Hope someone can help out. > > Gijs Schumacher, MSc > PhD candidate > > -------------------------------------- > Department of Political Science > VU University Amsterdam > > Contact: > Tel: +31(0)20 5986798 > Fax: +31(0)20 5986820 > Web: http://home.fsw.vu.nl/g.schumacher > Email: g.schumacher at vu.nl<mailto:g.schumacher at fsw.vu.nl> > > Visiting address: > Metropolitan > Buitenveldertselaan 2 > Room Z - 333 > > Mail: > De Boelelaan 1081 > 1081 HV Amsterdam > The Netherlands > > > [[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.