[R] extract half a matrix

[Spencer Graves]

 > A <- array(1:12, dim=c(3,4))
 > A[col(A)>row(A)]
[1]  4  7  8 10 11 12

This is described in Modern Applied Statistics with S (p. 43 of the 3rd 
edition;  I'm pretty sure I've seen it in the 4th edition, but I don't 
have that handy just now.)

hth.  spencer graves

Tord Snall wrote:
> Dear all,
> 
> I'm new to matrix operations in R. I couln't find a solution to the
> following problem among earlier help mails or in An introd to R, I guess
> because the question is really basic.
> 
> I want to extract all above the diagonal, i.e. from 
> 
>     1  2  3  4 
> 1   0 26 49 49 
> 2  26  0 44 40 
> 3  49 44  0 21 
> 4  49 40 21  0 
> 
> I want 
> 
> 26
> 49
> 44
> 49
> 40
> 21
> 
> 
> Thanks in advance!
> 
> 
> Sincerely,
> Tord
> 
> -----------------------------------------------------------------------
> Tord Snäll
> Avd. f växtekologi, Evolutionsbiologiskt centrum, Uppsala universitet
> Dept. of Plant Ecology, Evolutionary Biology Centre, Uppsala University
> Villavägen 14			
> SE-752 36 Uppsala, Sweden
> Tel: 018-471 28 82 (int +46 18 471 28 82) (work)
> Tel: 018-25 71 33 (int +46 18 25 71 33) (home)
> Fax: 018-55 34 19 (int +46 18 55 34 19) (work)
> E-mail: Tord.Snall at ebc.uu.se
> Check this: http://www.vaxtbio.uu.se/resfold/snall.htm!
> 
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