From: Rolf Turner <rolf_at_math.unb.ca>

Date: Wed 02 Mar 2005 - 07:24:50 EST

[3,] 2 3 0 0

[4,] 4 5 6 0

Michael Anyadike-Danes wrote:

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Mar 02 08:56:53 2005

Date: Wed 02 Mar 2005 - 07:24:50 EST

> x <- 1:6 # In real life x <- scan(<filename>). > m <- matrix(0,4,4) > m[row(m)<col(m)] <- x > m <- t(m) > m [,1] [,2] [,3] [,4] [1,] 0 0 0 0 [2,] 1 0 0 0

[3,] 2 3 0 0

[4,] 4 5 6 0

The fiddle with the transposing is needed because R puts data into matrices column-by-column, not row-by-row.

cheers,

Rolf Turner rolf@math.unb.ca

Michael Anyadike-Danes wrote:

> I have output from a program which produces a distance matrix I want

*> to read into a clustering program in R.
**>
**> The output is a .txt file and is 'almost' lower triangular in the
**> sense that it is just the triangle below the diagonal.
**>
**> So for example a 4-by-4 distance matrix appears as,
**>
**> 1
**>
**> 2 3
**>
**> 4 5 6
**>
**> i.e. it looks like a lower triangular of a 3-by3.
**>
**> I thought I might be able to use "diag" to add zeros but apparently not.
**>
**> It's a problem because my matrix is actually 1989-by-1989 not 4-by-4
**>
**> I would not be at all surprised if the solution is obvious but I cannot
**> quite see how to read this into R.
*

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Mar 02 08:56:53 2005

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