[R] Summing rows by years (each time separately)

[David Winsemius]

On Jan 8, 2012, at 1:57 PM, Andrew Gaska wrote:

> Dear all,
>
> I could not find an answer for the problem.
>
> I have a matrix and I want to sum rows in groups i.e. rows are  
> summed as
> long as rows of column 1 have some value (f.e. 2008 in it), then  
> again rows
> are summed as long as rows of column 2 have some value (f.e. 2009 in  
> it).
>

?aggregate

-- 
David.
> In case there is a repetition of value in column 1 in another group,  
> this
> group should be summed seperately.
>
> Example:
>
> I have such a matrix:
>
> *1.2008*	3	2	2
> *2.2008*	4	3	3
> * 3.2008*	5	4	4
> * 4.2008*	3	3	1
> *1.2009*	6	1	2
> *2.2009*	3	2	5
> *1.2010*	4	4	3
> * 2.2010*	3	3	2
> *3.2010*	1	5	3
> *4.2010*	2	2	2
> * 1.2008*	3	1	1
> *2.2008*	4	3	2
> *3.2008*	2	4	3
> *1.2009*	1	2	4
> *2.2009*	5	4	3
> *3.2009*	4	3	3
> *1.2010*	4	3	1
> *2.2010*	2	2	2
>
> The result should be like this:
>
> *2008*	15	12	10
> *2009*	9	3	7
> *2010*	10	14	10
> *2008*	9	8	6
> *2009*	10	9	10
> *2010*	6	5	3
>
>
> Could You help me with that?
>
> Yours,
> Andrew Gaska
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/Summing-rows-by-years-each-time-separately-tp4276428p4276428.html
> Sent from the R help mailing list archive at Nabble.com.
>
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> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
West Hartford, CT