[R] Retrieving the 2 row of "dist" computations

[Jeff08]

Hey, 

The code definitely works, but I may need a more elegant way to do it.
Rather than 5 rows, the full data contains 829 rows, so instead of d of
length 10, d will be of length 343206.


Jorge Ivan Velez wrote:
> 
> Hi there,
> 
> I am sure there is a better way to do it, but here is a suggestion:
> 
> res <- matrix(NA, ncol = 2, nrow = 5)
> for(i in 1:5) res[i, ] <- which(as.matrix(d) == sort(d)[i], arr.ind =
> TRUE)[1,]
> res
> 
> HTH,
> Jorge
> 
> 
> On Wed, Jun 9, 2010 at 11:30 PM, Jeff08 <> wrote:
> 
>>
>> Dear R Gurus,
>>
>> As you probably know, dist calculates the distance between every two rows
>> of
>> data. What I am interested in is the actual two rows that have the least
>> distance between them, rather than the numerical value of the distance
>> itself.
>>
>> For example, If the minimum distance in the following sample run is
>> d[14],
>> which is .3826119, and the rows are 4 & 6. I need to find a generic way
>> to
>> retrieve these rows, for a generic matrix of NRows (in this example
>> NRows=7)
>>
>> NCols=5
>> NRows=7
>> myMat<-matrix(runif(NCols*NRows), ncol=NCols)
>>
>> d<-dist(myMat)
>>
>>          1         2         3         4         5         6
>> 2 0.7202138
>> 3 0.7866527 0.9052319
>> 4 0.6105235 1.0754259 0.8897555
>> 5 0.5032729 1.0789359 0.9756421 0.4167131
>> 6 0.6007685 0.6949224 0.3826119 0.7590029 0.7994574
>> 7 0.9751200 1.2218754 1.0547197 0.5681905 0.7795579 0.8291303
>>
>> e<-sort.list(d)
>> e<-e[1:5]  ##Retrieve minimum 5 distances
>>
>> [1] 14 16  4 18  5
>> --
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>>
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>>
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

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