# Re: [R] Finding overlaps in vector

From: Johannes Graumann <johannes_graumann_at_web.de>
Date: Sat, 22 Dec 2007 11:12:45 +0100

Joh

Gabor Grothendieck wrote:

```> If we don't need any plotting we don't really need rect.hclust at
> all.  Split the output of cutree, instead.  Continuing from the
> prior code:
>
```

>> for(el in split(unname(vv), names(vv))) print(el)
```> [1] 0.00 0.45
> [1] 1
> [1] 2
> [1] 3.00 3.25 3.33 3.75 4.10
> [1] 5
> [1] 6.00 6.45
> [1] 7.0 7.1
> [1] 8
>
> On Dec 21, 2007 3:24 PM, Johannes Graumann <johannes_graumann_at_web.de>
> wrote:
```

>> Hm, hm, rect.hclust doesn't accept "plot=FALSE" and cutree doesn't retain
>> the indexes of membership ... anyway short of ripping out the guts of
>> rect.hclust to achieve the same result without an active graphics device?
>>
>> Joh
>>
>>
>> >> # cluster and plot
>> >> hc <- hclust(dist(v), method = "single")
>> >> plot(hc, lab = v)
>> >> cl <- rect.hclust(hc, h = .5, border = "red")
>> >>
>> >> # each component of list cl is one cluster. Print them out.
>> >> for(idx in cl) print(unname(v[idx]))
>> > [1] 8
>> > [1] 7.0 7.1
>> > [1] 6.00 6.45
>> > [1] 5
>> > [1] 3.00 3.25 3.33 3.75 4.10
>> > [1] 2
>> > [1] 1
>> > [1] 0.00 0.45
>> >
>> >> # a different representation of the clusters
>> >> vv <- v
>> >> names(vv) <- ct <- cutree(hc, h = .5)
>> >> vv
>> > 1 1 2 3 4 4 4 4 4 5 6 6 7 7
>> > 8
>> > 0.00 0.45 1.00 2.00 3.00 3.25 3.33 3.75 4.10 5.00 6.00 6.45 7.00 7.10
>> > 8.00
>> >
>> >
>> > On Dec 21, 2007 4:56 AM, Johannes Graumann <johannes_graumann_at_web.de>
>> > wrote:
>> >> <posted & mailed>
>> >>
>> >> Dear all,
>> >>
>> >> I'm trying to solve the problem, of how to find clusters of values in
>> >> a vector that are closer than a given value. Illustrated this might
>> >> look as follows:
>> >>
>> >> vector <- c(0,0.45,1,2,3,3.25,3.33,3.75,4.1,5,6,6.45,7,7.1,8)
>> >>
>> >> When using '0.5' as the proximity requirement, the following groups
>> >> would result:
>> >> 0,0.45
>> >> 3,3.25,3.33,3.75,4.1
>> >> 6,6.45
>> >> 7,7.1
>> >>
>> >> Jim Holtman proposed a very elegant solution in
>> >> http://tolstoy.newcastle.edu.au/R/e2/help/07/07/21286.html, which I
>> >> have modified and perused since he wrote it to me. The beauty of this
>> >> approach is that it will not only work for constant proximity
>> >> requirements as above, but also for overlap-windows defined in terms
>> >> of ppm around each value. Now I have an additional need and have found
>> >> no way (short of iteratively step through all the groups returned) to
>> >> figure out how to do that with Jim's approach: how to figure out that
>> >> 6,6.45 and 7,7.1 are separate clusters?
>> >>
>> >> Thanks for any hints, Joh
>> >>
```>
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