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

[David Winsemius]

On Jan 8, 2012, at 8:43 PM, William Dunlap wrote:

> In aggregate() you can use the following as your
> grouping ('by') variable
>   group <- cumsum(c(TRUE, year[-1] != y[-length(year)]))
> where 'year' is the column of your matrix containing
> the 2008, 2009, ...

I thought those were rownames and was expecting to see code along the  
lines of

grp = gsub("^.+\\.|\\*$", "",  rownames(mtx) )

-- 
David.
>
> Bill Dunlap
> Spotfire, TIBCO Software
> wdunlap tibco.com
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org 
>> ] On Behalf Of David Winsemius
>> Sent: Sunday, January 08, 2012 5:36 PM
>> To: Andrew Gaska
>> Cc: r-help at r-project.org
>> Subject: Re: [R] Summing rows by years (each time separately)
>>
>>
>> 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.
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius, MD
>> West Hartford, CT
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
West Hartford, CT