R help - May 2002 - Fwd: Re: Combining many dataframes from listings of objects?

> I want to combine (rbind) many dataframes into a single data frame, but
"automatically"
> specifying the names of the dataframes as listing of object names.
> E.g., combine these 18 df objects into one big df using something
conceptually like this :
> rbind(objects(pattern="*.df"))

Brian Ripley suggested that something along the lines of: 
do.call("rbind", objects(pattern="*.df"))


But I can't make this fly on vectors.  E.g.,  
>  objects.of.desire_objects(pattern="*.df")
> do.call("rbind.data.frame",list(as.name(objects.of.desire)))  #
do.call needs a list and must be of class 'name'
Unfortunately, only the first data.frame in the series is read and returned.


Any further nudges along the right direction anyone?

Thanks!




Derek N. Eder
G?teborgs Universitet
Institutionen f?r klinisk neurovetenskap - psykiatri
Sahlgrenska universitetssjukhuset SS/SU
Bl? straket 17b
SE 413 45  G?teborg
Sverige
Tlf. +46 (031) 34  2-6139  (office)
Tlf. +46 (031) 34 2-1283  (laboratory)
Tlf. +46 0709 / 7 2-1283 (mobil)
Fax. +46 (031) 82 81 63 
derek.eder at neuro.gu.se


Gothenburg University
Institute of Clinical Neuroscience,
Section for Psychiatry
Salhgrenska Hospital  SU/SS
SE 413 45  G?teborg
Sweden

-------------- next part --------------
An embedded message was scrubbed...
From: Prof Brian D Ripley <ripley at stats.ox.ac.uk>
Subject: Re: [R] Combining many dataframes from listings of objects?
Date: Wed, 15 May 2002 10:56:07 +0100 (GMT Daylight Time)
Size: 4732
Url:
https://stat.ethz.ch/pipermail/r-help/attachments/20020515/a5f0db46/attachment.mht

"Derek Eder" <Derek.Eder at neuro.gu.se> writes:
> > I want to combine (rbind) many dataframes into a single data frame,
but "automatically"
> > specifying the names of the dataframes as listing of object names.
> > E.g., combine these 18 df objects into one big df using something
conceptually like this :
> > rbind(objects(pattern="*.df"))
> 
> 
> Brian Ripley suggested that something along the lines of: 
do.call("rbind", objects(pattern="*.df"))
> 
> 
> But I can't make this fly on vectors.  E.g.,  
> 
> >  objects.of.desire_objects(pattern="*.df")
> > do.call("rbind.data.frame",list(as.name(objects.of.desire)))
# do.call needs a list and must be of class 'name'
> 
> Unfortunately, only the first data.frame in the series is read and
returned.
> 
> 
> Any further nudges along the right direction anyone?
How about this?

do.call("rbind", lapply(objects(pattern="*.df"),get))

or 

eval(as.call(c(as.name(rbind), lapply(objects(pattern="*.df"),
as.name))))

(NB: "How about" is code for "Not actually tried"!)
-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
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
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._