What do you mean by "compare"? 

In the two examples you give, it seems like you are trying to "compare" 
one cell with its adjacent neighbor in the next column, its adjacent 
neighbor in the next row, and its diagonally adjacent neighbor in the next 
column and row.  Is that right?

If I correctly understand the neighbors you are interested in comparing, 
and I make the assumption that the comparison you are making is the 
difference in the two values, then something like this might help.

m <- scan()
277.4 276.24 275.62 276.55 278.05
277.4 276.24 275.55 276.42 277.72
277.4 276.24 275.50 276.22 277.39
277.4 276.24 275.42 276.02 277.02
277.4 276.22 275.37 275.82 276.64

a <- matrix(m, byrow=T, nrow=5)
a

compare <- function(mat, i, j) {
        c1 <- mat[i, j] - mat[i, j+1]
        c2 <- mat[i, j] - mat[i+1, j+1]
        c3 <- mat[i, j] - mat[i+1, j]
        c(c1, c2, c3)
        }

compare(a, 1, 1)

compare(a, 1, 2)

Jean


`·.,,  ><(((º>   `·.,,  ><(((º>   `·.,,  ><(((º>

Jean V. Adams
Statistician
U.S. Geological Survey
Great Lakes Science Center
223 East Steinfest Road
Antigo, WI 54409  USA



From:
kokavolchkov <kokavolchkov@gmail.com>
To:
r-help@r-project.org
Date:
08/05/2011 07:17 AM
Subject:
[R] R compare cells in one matrix
Sent by:
r-help-bounces@r-project.org



Good morning!

Please, could you help me with the problem?

I have a matrix *144x73.*

An example of a matrix:

        [,1]     [,2]      [,3]      [,4]     [,5] 
 [1,] 277.4 276.24 275.62 276.55 278.05
 [2,] 277.4 276.24 275.55 276.42 277.72
 [3,] 277.4 276.24 275.50 276.22 277.39
 [4,] 277.4 276.24 275.42 276.02 277.02
 [5,] 277.4 276.22 275.37 275.82 276.64

And I want to *compare*its cells like this:

a11 and a12;
a11 and a21;
a11 and a22.

then

a12 and a22;
a12 and a13;
a12 and a23.

and so on in a cycle.
*Is there a function or a package that can be used for comparation?*

Thank you!

--
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