[R] Copying rows from a matrix using a vector of indices

[Spencer Graves]

	  I don't quite understand what you are asking.  Have you checked the 
sections on "Simple manipulations numbers and vectors", "Arrays and 
matrices", and "Lists and data frames" in the manual "An Introduction to 
R"?  If you still would like some help after this, PLEASE do read the 
posting guide! "http://www.R-project.org/posting-guide.html".  It can 
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	  spencer graves

Martin Lam wrote:

> Hi,
> 
> I am trying to use a vector of indices to select some
> rows from a matrix. But before I can do that I somehow
> need to convert 'combinations' into a list, since
> 'mode(combinations)' says it's 'numerical'. Any idea
> how I can do that?
> 
> library("combinat")
> 
> combinations <- t(combn(8,2))
> 
> indices <- c(sample(1:length(combinations),10))
> 
> # convert
> ???
> 
> subset <- combinations[indices]
> 
> Thanks in advance,
> 
> Martin
> 
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