[R] locate pattern in matrix

[William Dunlap]

What would you like to get from the following?
  0 1 0 0 0
  1 1 1 0 0
  1 1 1 1 0
  0 0 1 1 0
  0 0 1 1 1
  0 0 0 1 1

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
> Of email
> Sent: Thursday, January 09, 2014 11:03 PM
> To: r-help at r-project.org
> Subject: [R] locate pattern in matrix
> 
> Dear all,
> 
> I have a binary matrix
> 
> 0 0 0 0 0
> 1 1 1 0 0
> 1 1 1 0 0
> 0 0 0 0 0
> 0 0 0 1 1
> 0 0 0 1 1
> 
> I want to find the location of all the square and rectangular 1 blocks, like
> 
> First block in row=2, col=1 to row=3, col=3.
> Second block in row=5, col=4, to row=6, col=5.
> 
> How can I find such blocks of 1?
> 
> Thanks:
> John
> 
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