[R] How to stack the columns of matrix

[Bill.Venables@cmis.csiro.au]

Peter Schlattman asks:

>  -----Original Message-----
> From: 	Dr. Peter Schlattmann
> [mailto:schlatti at mailer.ukbf.fu-berlin.de] 
> Sent:	Wednesday, June 12, 2002 11:37 PM
> To:	r-help at stat.math.ethz.ch
> Subject:	[R] How to stack the columns of matrix
> 
> Dear all,
> 
> I need to stack the columns of a matrix with a variable number of columns.
> I am aware of 
> 
> new<-c(a[,1],a[,2])
> 
> if I have a matrix 'a' with e.g. two columns. For a simulation study I
> need to stack 
> the matrix with a variable number of columns. Is there a way to do this?
	[WNV]  In a sense they are already 'stacked', as you put it, in a
sense.  

	X[i, j] refers to the matrix element, X[k] refers to the kth element
of the column stacked matrix (unless k itself is a matrix, but that is
another story).

	To make it official with no going back you could use either

	new <- as.vector(a)
	new <- a; dim(new) <- NULL

	or a variety of other dodges.  After either of these new is the
stacked version of a.

	Bill Venables.

> Many thanks in advance
> Peter
> 
> 
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