R help - Jan 2009 - Newbie question about "grouping"

Hi folks:
 
I am a SQL guy who just downloaded and installed R yesterday.  I am
trying to evaluate some "complex" aggregations we are currently
performing with Syncsort (and have tried in Oracle) with R.  I have
loaded data in a dataframe and have performed some of the simple
aggregations on a subset of data.  What I do not see how to do though,
is to "group" the aggregations on a particular key value (e.g., sum
market_value over account_id).
 
If you can point me in the right direction I'd very much appreciate it.
 
Thanks!
 
John

	[[alternative HTML version deleted]]

?by
?aggregate
?ave

Further specifics might be forthcoming if self-contained example data  
and desired output were offered. The help pages will have worked  
examples, of course.

-- 
David Winsemius


On Jan 28, 2009, at 9:13 AM, Rixon, John C. wrote:
> Hi folks:
>
> I am a SQL guy who just downloaded and installed R yesterday.  I am
> trying to evaluate some "complex" aggregations we are currently
> performing with Syncsort (and have tried in Oracle) with R.  I have
> loaded data in a dataframe and have performed some of the simple
> aggregations on a subset of data.  What I do not see how to do though,
> is to "group" the aggregations on a particular key value (e.g.,
sum
> market_value over account_id).
>
> If you can point me in the right direction I'd very much appreciate  
> it.
>
> Thanks!
>
> John
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> 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.

Some useful commands are:

by(), aggregate(), ave(), split().

eg
   by(market_value, account_id, sum)

         -thomas


On Wed, 28 Jan 2009, Rixon, John C. wrote:
> Hi folks:
>
> I am a SQL guy who just downloaded and installed R yesterday.  I am
> trying to evaluate some "complex" aggregations we are currently
> performing with Syncsort (and have tried in Oracle) with R.  I have
> loaded data in a dataframe and have performed some of the simple
> aggregations on a subset of data.  What I do not see how to do though,
> is to "group" the aggregations on a particular key value (e.g.,
sum
> market_value over account_id).
>
> If you can point me in the right direction I'd very much appreciate it.
>
> Thanks!
>
> John
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>
Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle

On Wed, Jan 28, 2009 at 8:13 AM, Rixon, John C. <JCRixon at
wellington.com> wrote:
> Hi folks:
>
> I am a SQL guy who just downloaded and installed R yesterday.  I am
> trying to evaluate some "complex" aggregations we are currently
> performing with Syncsort (and have tried in Oracle) with R.  I have
> loaded data in a dataframe and have performed some of the simple
> aggregations on a subset of data.  What I do not see how to do though,
> is to "group" the aggregations on a particular key value (e.g.,
sum
> market_value over account_id).
>
> If you can point me in the right direction I'd very much appreciate it.
Have a look at the plyr package, http://had.co.nz/plyr, and associated
documentation. If you're doing pivot table type aggregations, you
might also want to have a look at the reshape package,
http://had.co.nz/reshape.


Hadley

-- 
http://had.co.nz/