Finding overlaps in vector
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