[R] Extracting clusters from Data Frame

Gustaf Rydevik gustaf.rydevik at gmail.com
Mon Dec 10 15:06:03 CET 2007

On Dec 10, 2007 2:28 PM, Johannes Graumann <johannes_graumann at web.de> wrote:
> Hello,
> I have a large data frame (1006222 rows), which I subject to a crude
> clustering attempt that results in a vector stating whether the datapoint
> represented by a row belongs to a cluster or not. Conceptually this looks
> something like this:
> Value   Cluster?
> 0.01    FALSE
> 0.03    TRUE
> 0.04    TRUE
> 0.05    TRUE
> 0.07    FALSE
> ...
> What I'm looking for is an efficient strategy to extract all consecutive
> rows associated with "TRUE" as a single cluster (data.frame
> representation?) without cluttering memory with thousends of data.frames.
> I was thinking of an independent data.frame that would contain a column of
> lists that reference all indexes from the big one which are contained in
> one cluster ...
> Can anyone kindly nudge me and let me know how to deal with this
> efficiently?
> Joh

How about :

##Then, to get all original data belonging to cluster three:

Not the neatest solution, but I'm sure someone here can improve on it.

Gustaf Rydevik, M.Sci.
tel: +46(0)703 051 451
address:Essingetorget 40,112 66 Stockholm, SE

More information about the R-help mailing list