Aggregation using list with Hmisc summarize function
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