Oi Milton,
Is this what you are after?
x=read.table("miltondat.txt")
x
V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1 0 0 0 0 0 0 0 0 0 0
2 0 0 0 0 0 1 1 1 0 0
3 0 0 0 0 0 1 1 1 0 0
4 0 0 0 0 0 0 0 0 0 0
5 0 0 2 2 2 0 0 0 0 0
6 0 0 0 2 2 2 0 0 0 0
7 0 0 2 2 2 2 2 2 0 0
8 0 0 0 0 0 0 0 0 0 0
idx=which(x==2,arr.ind=T) #Index of observations with values == 2 . Notice
the use of arr.ind=t to get the rows and columns of the observations
idx
row col
5 5 3
7 7 3
5 5 4
6 6 4
7 7 4
5 5 5
6 6 5
7 7 5
6 6 6
7 7 6
7 7 7
7 7 8
range(idx[,"row"]) #gives you the min and max of the rows with x==2
[1] 5 7
range(idx[,"col"])#gives you the min and max of the columns with x==2
[1] 3 8
You can refine this and wrap it in a function to make reports in a more
suitable form
Regards
Francisco
Dr. Francisco J. Zagmutt
College of Veterinary Medicine and Biomedical Sciences
Colorado State University
From: Milton Cezar Ribeiro <[EMAIL PROTECTED]>
To: r-help@stat.math.ethz.ch
Subject: [R] identify extremes positions of values into matrix
Date: Fri, 3 Nov 2006 11:25:32 -0300 (ART)
Hi R-friends around world!
I have a matrix that looks like bellow one.
Each cell are filled with values 0, 1 or 2.
In fact I have a lot of 512x512 matrices, with
values varying from 0 to 999.
I need to retrieve the left and right columns
and the top and botton lines of the matrix
where occours for example the value 2.
Column and row labels are included at the example.
1234567890
1 0000000000
2 0000011100
3 0000011100
4 0000000000
5 0022200000
6 0002220000
7 0022222200
8 0000000000
At this example, the right answer are:
collumns 3 and 8
lines 5 and 7
Any idea of how can I solve this?
Kind regards,
Miltinho
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