[R] Extracting clusters from Data Frame
johannes_graumann at web.de
Tue Dec 11 20:36:39 CET 2007
Gustaf Rydevik wrote:
> On Dec 10, 2007 2:28 PM, Johannes Graumann <johannes_graumann at web.de>
>> 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
> 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.
Thank you for this example! "rle" was indeed what safed my day!
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