Dear list, I want to retrieve a specific data from a matrix with 3000 columns. The matrix has island ID as its rows and species ID as its columns. There are 20 rows and 3000 columns in the matrix. (Island ID: Species 1- Species 20/ species ID: Species 1- Species 3000) The contents of the matrix grids is 1 or 0, for presence and absence. Now I would like to check in Island 1 which species is 1. (Island 1 as row 2) Please kindly advise how to code the command and thank you in advance. Elaine [[alternative HTML version deleted]]
On 11-09-2013, at 09:38, Elaine Kuo <elaine.kuo.tw at gmail.com> wrote:> Dear list, > > I want to retrieve a specific data from a matrix with 3000 columns. > The matrix has island ID as its rows and species ID as its columns. > There are 20 rows and 3000 columns in the matrix. > (Island ID: Species 1- Species 20/ species ID: Species 1- Species 3000) > The contents of the matrix grids is 1 or 0, for presence and absence. > > Now I would like to check in Island 1 which species is 1. (Island 1 as row > 2) > Please kindly advise how to code the command and thank you in advance.What have you tried? Something like this perhaps which(datamatrix[2,] == 1) or which(datamatrix[2,] == 1L) Berend
Hi,
set.seed(24)
mat1<-
matrix(sample(0:1,20*100,replace=TRUE),ncol=100,dimnames=list(paste0("Species",1:20),paste0("Species",1:100)))
?which(mat1[1,]==1)
#or
which(!is.na(match(mat1[1,],1)))
A.K.
----- Original Message -----
From: Elaine Kuo <elaine.kuo.tw at gmail.com>
To: "r-help at r-project.org" <r-help at r-project.org>
Cc:
Sent: Wednesday, September 11, 2013 3:38 AM
Subject: [R] to retrieve specific data from a matrix
Dear list,
I want to retrieve a specific data from a matrix with 3000 columns.
The matrix has island ID as its rows and species ID as its columns.
There are 20 rows and 3000 columns in the matrix.
(Island ID: Species 1- Species 20/ species ID: Species 1- Species 3000)
The contents of the matrix grids is 1 or 0, for presence and absence.
Now I would like to check in Island 1 which species is 1. (Island 1 as row
2)
Please kindly advise how to code the command and thank you in advance.
Elaine
??? [[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.