Re: [R] sum a particular column by group

Thanks for your help. Finally, I got it. From: Dennis Murphy [mailto:djmu...@gmail.com] Sent: Friday, February 05, 2010 12:20 PM To: Fang (Betty) Yang Cc: r-help@r-project.org Subject: Re: [R] sum a particular column by group Hi: This is not an elegant solution by any means, but it gets

Re: [R] sum a particular column by group

Hi: This is not an elegant solution by any means, but it gets what you want...using the data frame from your bootstrap sample, # All combinations of the three factors xx <- with(beds, expand.grid(Region = levels(Region), Gender = levels(Gender), Agegr = levels(Agegr)) ) > dim(xx) [

[R] sum a particular column by group

Dear all, I have a table like this: > eds R.ID Region Gender Agegr Time nvisits 11 A F 60--64 1:00 1 22 OF 55--591:20 1 33 OF 55--59 3:45 3 44 S