R help - Oct 2010 - aggregate text column by a few rows

Hi, R function aggregate can only take summary stats functions, can I
aggregate text columns?  For example, for the dataframe below, 

 
> a <- rbind(data.frame(id=1, name='Tom',
hobby='fishing'),data.frame(id=1, name='Tom',
hobby='reading'),data.frame(id=2, name='Mary',
hobby='reading'),data.frame(id=3, name='John',
hobby='boating'),data.frame(id=2, name='Mary',
hobby='running'))
> a
  id name   hobby

1  1  Tom fishing

2  1  Tom reading

3  2 Mary reading

4  3 John boating

5  2 Mary running

 

 

I want output as 
>b
id name hobbies

1 Tom    fishing reading

2 Mary reading running

3 John boating

 

 

 

Thanks,

Richard

 


	[[alternative HTML version deleted]]

try this using sqldf:
> a
  id name   hobby
1  1  Tom fishing
2  1  Tom reading
3  2 Mary reading
4  3 John boating
5  2 Mary running
> require(sqldf)
> sqldf('select name, group_concat(hobby) hobby from a group by id',
method='raw')
  name           hobby
1  Tom fishing,reading
2 Mary reading,running
3 John         boating


On Thu, Oct 7, 2010 at 11:52 AM, Tan, Richard <RTan at panagora.com>
wrote:
> Hi, R function aggregate can only take summary stats functions, can I
> aggregate text columns? ?For example, for the dataframe below,
>
>
>
>> a <- rbind(data.frame(id=1, name='Tom',
> hobby='fishing'),data.frame(id=1, name='Tom',
> hobby='reading'),data.frame(id=2, name='Mary',
> hobby='reading'),data.frame(id=3, name='John',
> hobby='boating'),data.frame(id=2, name='Mary',
hobby='running'))
>
>> a
>
> ?id name ? hobby
>
> 1 ?1 ?Tom fishing
>
> 2 ?1 ?Tom reading
>
> 3 ?2 Mary reading
>
> 4 ?3 John boating
>
> 5 ?2 Mary running
>
>
>
>
>
> I want output as
>
>>b
>
> id name hobbies
>
> 1 Tom ? ?fishing reading
>
> 2 Mary reading running
>
> 3 John boating
>
>
>
>
>
>
>
> Thanks,
>
> Richard
>
>
>
>
> ? ? ? ?[[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.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

Try this:

aggregate(hobby ~ id + name, a, FUN = toString)


On Thu, Oct 7, 2010 at 12:52 PM, Tan, Richard <RTan@panagora.com> wrote:
> Hi, R function aggregate can only take summary stats functions, can I
> aggregate text columns?  For example, for the dataframe below,
>
>
>
> > a <- rbind(data.frame(id=1, name='Tom',
> hobby='fishing'),data.frame(id=1, name='Tom',
> hobby='reading'),data.frame(id=2, name='Mary',
> hobby='reading'),data.frame(id=3, name='John',
> hobby='boating'),data.frame(id=2, name='Mary',
hobby='running'))
>
> > a
>
>  id name   hobby
>
> 1  1  Tom fishing
>
> 2  1  Tom reading
>
> 3  2 Mary reading
>
> 4  3 John boating
>
> 5  2 Mary running
>
>
>
>
>
> I want output as
>
> >b
>
> id name hobbies
>
> 1 Tom    fishing reading
>
> 2 Mary reading running
>
> 3 John boating
>
>
>
>
>
>
>
> Thanks,
>
> Richard
>
>
>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@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.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

Richard -
   Yes, you certainly can use aggregate to acheive what you want:
> aggregate(a$hobby,a['name'],paste,collapse=' ')
   name               x
1  Tom fishing reading
2 Mary reading running
3 John         boating

 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu


On Thu, 7 Oct 2010, Tan, Richard wrote:
> Hi, R function aggregate can only take summary stats functions, can I
> aggregate text columns?  For example, for the dataframe below,
>
>
>
>> a <- rbind(data.frame(id=1, name='Tom',
> hobby='fishing'),data.frame(id=1, name='Tom',
> hobby='reading'),data.frame(id=2, name='Mary',
> hobby='reading'),data.frame(id=3, name='John',
> hobby='boating'),data.frame(id=2, name='Mary',
hobby='running'))
>
>> a
>
>  id name   hobby
>
> 1  1  Tom fishing
>
> 2  1  Tom reading
>
> 3  2 Mary reading
>
> 4  3 John boating
>
> 5  2 Mary running
>
>
>
>
>
> I want output as
>
>> b
>
> id name hobbies
>
> 1 Tom    fishing reading
>
> 2 Mary reading running
>
> 3 John boating
>
>
>
>
>
>
>
> Thanks,
>
> Richard
>
>
>
>
> 	[[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.
>