[R] Aggregate data frame across columns

[Jeff Newmiller]

The best way to get an answer is to provide sample data and desired results (computed by hand or by any other available means). See http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example. 

In the vague question begets a vague answer department, I would use melt from the reshape package, and make some columns that contain unique key values for each time interval, and then use aggregate or ddply from the plyr package.
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Sent from my phone. Please excuse my brevity.

Keith Weintraub <kw1958 at gmail.com> wrote:

>Folks,
>  I have a data frame with columns 200401, 200402, ..., 201207, 201208.
>
>These represent years/months. What would be the best way to sum these
>columns by year? What about by quarter?
>
>Thanks for your time,
>KW
>
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