I take it you want to split the matrix into sub-matrices for which some
collection of columns is constant. In your case this is the last four columns.
Here's an idea:
> z <- matrix(c(13,1,1,1,1,12,0,0,0,0,8,1,0,1,1,8,0,1,0,0,
+ 10,1,1,1,1,3,0,1,0,0,3,1,0,1,1,6,1,1,1,1),8,5,byrow = T)
> z
[,1] [,2] [,3] [,4] [,5]
[1,] 13 1 1 1 1
[2,] 12 0 0 0 0
[3,] 8 1 0 1 1
[4,] 8 0 1 0 0
[5,] 10 1 1 1 1
[6,] 3 0 1 0 0
[7,] 3 1 0 1 1
[8,] 6 1 1 1 1
> ind <- do.call(paste, data.frame(z[, 2:5]))
> split(data.frame(z), ind)
$`0 0 0 0`
X1 X2 X3 X4 X5
2 12 0 0 0 0
$`0 1 0 0`
X1 X2 X3 X4 X5
4 8 0 1 0 0
6 3 0 1 0 0
$`1 0 1 1`
X1 X2 X3 X4 X5
3 8 1 0 1 1
7 3 1 0 1 1
$`1 1 1 1`
X1 X2 X3 X4 X5
1 13 1 1 1 1
5 10 1 1 1 1
8 6 1 1 1 1
>
Bill Venables
http://www.cmis.csiro.au/bill.venables/
-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
Behalf Of kathie
Sent: Tuesday, 28 July 2009 8:47 AM
To: r-help@r-project.org
Subject: [R] Splitting matrix into several small matrices
Dear R users...
I need to split this matrix(or dataframe), for example,
z <- matrix(c(13,1,1,1,1,12,0,0,0,0,8,1,0,1,1,8,0,1,0,0,
10,1,1,1,1,3,0,1,0,0,3,1,0,1,1,6,1,1,1,1),8,5,byrow = T)
> z
[,1] [,2] [,3] [,4] [,5]
[1,] 13 1 1 1 1
[2,] 12 0 0 0 0
[3,] 8 1 0 1 1
[4,] 9 0 1 0 0
[5,] 10 1 1 1 1
[6,] 3 0 1 0 0
[7,] 3 1 0 1 1
[8,] 6 1 1 1 1
(actually, z matrix is big, about 1000*15 matrix)
to 4 matrices like this way,
#- 1st matrix--------------------------------------
13 1 1 1 1
10 1 1 1 1
6 1 1 1 1
#- 2nd matrix--------------------------------------
12 0 0 0 0
#- 3rd matrix--------------------------------------
8 1 0 1 1
3 1 0 1 1
#- 4th matrix--------------------------------------
9 0 1 0 0
3 0 1 0 0
Any comments will be greatly appreciated.
Kathryn Lord
--
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