R help - Mar 2000 - For the record: how to merge data frames vertically

Hello,

to save searching time in the S-news archive, here is the simple solution to
merge data frames vertically (cols must be equivalent, of course). The
frames must be components of a list, such as produced by
framelist<-split(bigframe,factor).

bigframe2<-do.call("rbind",framelist)

# posted to S-news by Bill Venables, found in summary message
http://lib.stat.cmu.edu/s-news/Burst/13564

The result is identical to bigframe with the exception of the rownames.
Those seem to be generated by pasting the respective component name and each
rowname (maybe to prevent non-unique rownames?). To keep rownames, I use

rownames(bigframe2)<-unlist(lapply(framelist,rownames))

Now, all I wonder is, why does this solution work and
"rbind(framelist)"
does not? (gives "Error in rbind(...) : cannot create a matrix from these
types"). To my untrained eye, the two look identical...

Cheers

Kaspar

-- 

Kaspar Pflugshaupt
Geobotanisches Institut
Zuerichbergstr. 38
CH-8044 Zuerich

Tel. ++41 1 632 43 19
Fax  ++41 1 632 12 15

mailto:pflugshaupt at geobot.umnw.ethz.ch
privat:pflugshaupt at mails.ch
http://www.geobot.umnw.ethz.ch

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at
stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._

On Thu, 9 Mar 2000, Kaspar Pflugshaupt wrote:
> Hello,
> 
> to save searching time in the S-news archive, here is the simple solution
to
> merge data frames vertically (cols must be equivalent, of course). The
To avoid confusion, that is not the usual meaning of `merge', but
of concatenate, say.
> frames must be components of a list, such as produced by
> framelist<-split(bigframe,factor).
> 
> bigframe2<-do.call("rbind",framelist)
> 
> # posted to S-news by Bill Venables, found in summary message
> http://lib.stat.cmu.edu/s-news/Burst/13564
> 
> The result is identical to bigframe with the exception of the rownames.
> Those seem to be generated by pasting the respective component name and
each
> rowname (maybe to prevent non-unique rownames?). To keep rownames, I use
> 
> rownames(bigframe2)<-unlist(lapply(framelist,rownames))
> 
> Now, all I wonder is, why does this solution work and
"rbind(framelist)"
> does not? (gives "Error in rbind(...) : cannot create a matrix from
these
> types"). To my untrained eye, the two look identical...
In rbind(framelist) the argument is a single list.  do.call creates a call
in which framelist is mapped to several arguments.

There seems to be a lack of clarity in what cbind and rbind do, and I have
expanded the help page for the next patch release.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at
stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._