[R] Extracting clusters from Data Frame

Johannes Graumann johannes_graumann at web.de
Mon Dec 10 14:28:19 CET 2007


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



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