[R] splitting matrices

[David L Carlson]

Alternatively you could use

dim(dd) <- c(31, 36, 12)

That will give you an array in which each small matrix is defined as

dd[,1:36,]

You can work with that directly, or if you want the separate matrices to be
represented by the third index:

ddd <- aperm(dd, c(1, 3, 2))

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of MacQueen, Don
> Sent: Thursday, January 03, 2013 10:57 AM
> To: eliza botto; r-help at r-project.org
> Subject: Re: [R] splitting matrices
> 
> This example illustrates a method that may do what you want.
> 
> ## split a 20x5 matrix into five 4x5 matrices
> xmat <- matrix(1:100, nrow=20, ncol=5, byrow=TRUE)
> xsplit <- rep( 1:5, times= rep(4,5))
> tmp <- split.data.frame(xmat,xsplit)
> 
> You will need to change xsplit to fit your dimensions.
> 
> -Don
> 
> 
> --
> Don MacQueen
> 
> Lawrence Livermore National Laboratory
> 7000 East Ave., L-627
> Livermore, CA 94550
> 925-423-1062
> 
> 
> 
> 
> 
> On 1/3/13 8:40 AM, "eliza botto" <eliza_botto at hotmail.com> wrote:
> 
> >
> >
> >Dear useRs,
> >i want to split a matrix having 1116rows and 12 columns. i want to
> split
> >that matrix into 36 small matrices each having 12 columns and 31 rows.
> >The big matrix should be splitted row wise. which means that the first
> >small matrix should copy values which are in first 31 rows and 12
> columns
> >of the big matrix. similarly 2nd small matrix should contain values
> from
> >32nd to 63rd row of the big matrix and so on. on the whole i want to
> have
> >36 small matrices.i tried
> >dim(dd) <- c(31,12,35)
> >but the result are not stisfactory...
> >thanks in advance
> >elisa
> >	[[alternative HTML version deleted]]
> >
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