use a matrix of n x 2 to index. For details: sec. 5.3 "Index matrices" in the
introduction.
HTH Claudia
Nils Rüfenacht wrote:
Dear all!
I'm trying to get multiple values from a matrix by using a single command.
Given a matrix A
A <- matrix(seq(1,9),nrow=3,ncol=3)
How can I get e.g. the values A[1,2] = 4 and A[3,3] = 9 with a single
command and without using any loop? My first idea was to generate a row-
and a column vector for the indices, i.e. c(1,3) indicating row number 1
(for A[1,2]) and row number 3 (for A[3,3]) and similar for
column-indices. Then I've tried to call
A[c(1,3),c(2,3)]
but instead of 4 , 9 the result is
[,1] [,2]
[1,] 4 7
[2,] 6 9
Any suggestions?
Regards, Nils
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--
Claudia Beleites
Dipartimento dei Materiali e delle Risorse Naturali
Università degli Studi di Trieste
Via Alfonso Valerio 6/a
I-34127 Trieste
phone: +39 0 40 5 58-37 68
email: cbelei...@units.it
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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.
