R help - Sep 2007 - stacking data frames with different variables

Hi All,

If I need to stack two data frames, I can use rbind, but it requires
that all variables exist in both sets. I can make that happen, but other
stat packages would figure out where the differences were, add the
missing variables to each, set their values to missing and stack them.
Is there a more automatic way to do that in R?

Below is an example program.

Thanks,
Bob

# Top data frame has two variables.
x <- c(1,2)
y <- c(1,2)

top <- data.frame(x,y)
top

# Bottom data frame has only one of them.
x <- c(3,4)
bottom <- data.frame(x)
bottom

# So rbind won't work.
rbind(top, bottom)

# After figuring out where the mismatches are I can 
# make the two DFs the same manually.
bottom <- data.frame( bottom, y=NA)
bottom

# Now I get the desired result.
both <- rbind(top,bottom)
both

========================================================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, 
News: http://listserv.utk.edu/archives/statnews.html

Have a look at rbind.fill in the reshape package.

Hadley

On 9/9/07, Muenchen, Robert A (Bob) <muenchen at utk.edu>
wrote:
> Hi All,
>
> If I need to stack two data frames, I can use rbind, but it requires
> that all variables exist in both sets. I can make that happen, but other
> stat packages would figure out where the differences were, add the
> missing variables to each, set their values to missing and stack them.
> Is there a more automatic way to do that in R?
>
> Below is an example program.
>
> Thanks,
> Bob
>
> # Top data frame has two variables.
> x <- c(1,2)
> y <- c(1,2)
>
> top <- data.frame(x,y)
> top
>
> # Bottom data frame has only one of them.
> x <- c(3,4)
> bottom <- data.frame(x)
> bottom
>
> # So rbind won't work.
> rbind(top, bottom)
>
> # After figuring out where the mismatches are I can
> # make the two DFs the same manually.
> bottom <- data.frame( bottom, y=NA)
> bottom
>
> # Now I get the desired result.
> both <- rbind(top,bottom)
> both
>
> ========================================================> 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,
> News: http://listserv.utk.edu/archives/statnews.html
>
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>

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