[R] how to get row name using the which function

[Downey, Patrick]

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

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Email: g.schumacher at vu.nl<mailto:g.schumacher at fsw.vu.nl>

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