R help - Dec 2006 - Aggregation using list with Hmisc summarize function

Hi All,

 

I'm using the Hmisc summarize function and used list instead of llist to
provide the by variables. It generated an error message. Is this a bug,
or do I misunderstand how Hmisc works with lists? The program below
demonstrates the error message.

 

Thanks,

Bob

 

x<-1:8

group <- c(1,1,1,1,2,2,2,2)

gender<- c(1,2,1,2,1,2,1,2)

 

mydata<-data.frame(x,group,gender)

attach(mydata)

 

# Creating a list using Hmisc llist works:

summarize(x, by=llist(group,gender), FUN=mean, na.rm=TRUE) 

 

# Creating a list using built-in list function does not:

summarize(x, by= list(group,gender), FUN=mean, na.rm=TRUE)

 

========================================================Bob Muenchen (pronounced
Min'-chen), Manager
Statistical Consulting Center
U of TN Office of Information Technology
200 Stokely Management Center, Knoxville, TN 37996-0520
Voice: (865) 974-5230 
FAX: (865) 974-4810
Email: muenchen@utk.edu
Web: http://oit.utk.edu/scc <http://oit.utk.edu/scc> , 
News: http://listserv.utk.edu/archives/statnews.html
<http://listserv.utk.edu/archives/statnews.html> 
========================================================
 


	[[alternative HTML version deleted]]

Muenchen, Robert A (Bob) wrote:
> Hi All,
> 
>  
> 
> I'm using the Hmisc summarize function and used list instead of llist
to
> provide the by variables. It generated an error message. Is this a bug,
> or do I misunderstand how Hmisc works with lists? The program below
> demonstrates the error message.
> 
>  
> 
> Thanks,
> 
> Bob
> 
>  
> 
> x<-1:8
> 
> group <- c(1,1,1,1,2,2,2,2)
> 
> gender<- c(1,2,1,2,1,2,1,2)
> 
>  
> 
> mydata<-data.frame(x,group,gender)
> 
> attach(mydata)
> 
>  
> 
> # Creating a list using Hmisc llist works:
> 
> summarize(x, by=llist(group,gender), FUN=mean, na.rm=TRUE) 
> 
>  
> 
> # Creating a list using built-in list function does not:
> 
> summarize(x, by= list(group,gender), FUN=mean, na.rm=TRUE)
Use llist so summarize will know how to label the output.

Also your attach( ) is not functional as your variables are already in 
the search path.  Whenever you do need to attach, consider the use of 
with( ) instead.

Frank
> 
>  
> 
> ========================================================> Bob Muenchen
(pronounced Min'-chen), Manager
> Statistical Consulting Center
> U of TN Office of Information Technology

-- 
Frank E Harrell Jr   Professor and Chair           School of Medicine
                      Department of Biostatistics   Vanderbilt University

Note that you don't really need list or llist in this case:

summarize(x, by = mydata[2:3], FUN = mean, na.rm = TRUE)

Also you could use aggregate:

aggregate(mydata[1], mydata[2:3], mean, na.rm = TRUE)


On 12/28/06, Muenchen, Robert A (Bob) <muenchen at utk.edu>
wrote:
> Hi All,
>
>
>
> I'm using the Hmisc summarize function and used list instead of llist
to
> provide the by variables. It generated an error message. Is this a bug,
> or do I misunderstand how Hmisc works with lists? The program below
> demonstrates the error message.
>
>
>
> Thanks,
>
> Bob
>
>
>
> x<-1:8
>
> group <- c(1,1,1,1,2,2,2,2)
>
> gender<- c(1,2,1,2,1,2,1,2)
>
>
>
> mydata<-data.frame(x,group,gender)
>
> attach(mydata)
>
>
>
> # Creating a list using Hmisc llist works:
>
> summarize(x, by=llist(group,gender), FUN=mean, na.rm=TRUE)
>
>
>
> # Creating a list using built-in list function does not:
>
> summarize(x, by= list(group,gender), FUN=mean, na.rm=TRUE)
>
>
>
> ========================================================> Bob Muenchen
(pronounced Min'-chen), Manager
> Statistical Consulting Center
> U of TN Office of Information Technology
> 200 Stokely Management Center, Knoxville, TN 37996-0520
> Voice: (865) 974-5230
> FAX: (865) 974-4810
> Email: muenchen at utk.edu
> Web: http://oit.utk.edu/scc <http://oit.utk.edu/scc> ,
> News: http://listserv.utk.edu/archives/statnews.html
> <http://listserv.utk.edu/archives/statnews.html>
> ========================================================>
>
>
>
>        [[alternative HTML version deleted]]
>
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