[R] Re: your mail

[Thomas Lumley]

On Sat, 14 Oct 2000, niels Waller wrote:

> 
> 
> 
> Dear colleagues,
> 
> I suspect there is a simple answer to this question -- but I cannot find it.
> 
> Suppose I have a list of matrices.  I want to pull out an element (such as
> row 1, col 2) from each matrix.  Do I need a loop to do this? Or is there an
> easy way to index this?
> 
> Let Z denote the list of matrices.  All matrices have the same order.  I
> want something like
>   Z[[.]][1,2]     (which of course will not work, but you get the idea)
> 

  lapply(Z,function(zi) zi[1,2])

will work. You may want to wrap this in unlist() to get a vector instead
of a list.

	-thomas

Thomas Lumley
Assistant Professor, Biostatistics
University of Washington, Seattle

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