There is probably a very simple elegant way to do this, but I have been
unable to find it. Here is a toy example. Suppose I have a list of data
frames like this.
print(x <-
list('1'=data.frame(id=1:4,expand.grid(x1=0:1,x2=0:1)),'2'=data.frame(id=5:8,expand.grid(x1=2:3,x2=2:3))))
$`1`
id x1 x2
1 1 0 0
2 2 1 0
3 3 0 1
4 4 1 1
$`2`
id x1 x2
1 5 2 2
2 6 3 2
3 7 2 3
4 8 3 3
The real application will have more than 2 elements so I'm looking for a
general approach. I basically want to rbind the data frames in each list
element and add a variable that adds the element name. In this example
the result would look something like this.
rbind(data.frame(set='1',x[[1]]),data.frame(set='2',x[[2]]))
set id x1 x2
1 1 1 0 0
2 1 2 1 0
3 1 3 0 1
4 1 4 1 1
5 2 5 2 2
6 2 6 3 2
7 2 7 2 3
8 2 8 3 3
Obviously, for 2 elements the simple rbind works but I would like a
general solution for arbitrary length lists. Hopefully that is clear.
Kevin
--
Kevin E. Thorpe
Head of Biostatistics, Applied Health Research Centre (AHRC)
Li Ka Shing Knowledge Institute of St. Michael's Hospital
Assistant Professor, Dalla Lana School of Public Health
University of Toronto
email: kevin.thorpe at utoronto.ca Tel: 416.864.5776 Fax: 416.864.3016
Hi Kevin, There may be a more elegant way but the following do.call and lapply should solve your problem. do.call(rbind, lapply(seq(length(x)), function(i) data.frame(set=i, x[[i]]))) Regards, Charles On Fri, Nov 4, 2016 at 7:37 AM, Kevin E. Thorpe <kevin.thorpe at utoronto.ca> wrote:> There is probably a very simple elegant way to do this, but I have been > unable to find it. Here is a toy example. Suppose I have a list of data > frames like this. > > print(x <- list('1'=data.frame(id=1:4,expand.grid(x1=0:1,x2=0:1)),'2'> data.frame(id=5:8,expand.grid(x1=2:3,x2=2:3)))) > $`1` > id x1 x2 > 1 1 0 0 > 2 2 1 0 > 3 3 0 1 > 4 4 1 1 > > $`2` > id x1 x2 > 1 5 2 2 > 2 6 3 2 > 3 7 2 3 > 4 8 3 3 > > The real application will have more than 2 elements so I'm looking for a > general approach. I basically want to rbind the data frames in each list > element and add a variable that adds the element name. In this example the > result would look something like this. > > rbind(data.frame(set='1',x[[1]]),data.frame(set='2',x[[2]])) > set id x1 x2 > 1 1 1 0 0 > 2 1 2 1 0 > 3 1 3 0 1 > 4 1 4 1 1 > 5 2 5 2 2 > 6 2 6 3 2 > 7 2 7 2 3 > 8 2 8 3 3 > > Obviously, for 2 elements the simple rbind works but I would like a > general solution for arbitrary length lists. Hopefully that is clear. > > Kevin > > -- > Kevin E. Thorpe > Head of Biostatistics, Applied Health Research Centre (AHRC) > Li Ka Shing Knowledge Institute of St. Michael's Hospital > Assistant Professor, Dalla Lana School of Public Health > University of Toronto > email: kevin.thorpe at utoronto.ca Tel: 416.864.5776 Fax: 416.864.3016 > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posti > ng-guide.html > and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]
Hi, You have also "rbindlist()" function in package "data.table" that does exactly what you need. Kind Regards, Carlos Ortega www.qualityexcellence.es 2016-11-04 13:37 GMT+01:00 Kevin E. Thorpe <kevin.thorpe at utoronto.ca>:> There is probably a very simple elegant way to do this, but I have been > unable to find it. Here is a toy example. Suppose I have a list of data > frames like this. > > print(x <- list('1'=data.frame(id=1:4,expand.grid(x1=0:1,x2=0:1)),'2'> data.frame(id=5:8,expand.grid(x1=2:3,x2=2:3)))) > $`1` > id x1 x2 > 1 1 0 0 > 2 2 1 0 > 3 3 0 1 > 4 4 1 1 > > $`2` > id x1 x2 > 1 5 2 2 > 2 6 3 2 > 3 7 2 3 > 4 8 3 3 > > The real application will have more than 2 elements so I'm looking for a > general approach. I basically want to rbind the data frames in each list > element and add a variable that adds the element name. In this example the > result would look something like this. > > rbind(data.frame(set='1',x[[1]]),data.frame(set='2',x[[2]])) > set id x1 x2 > 1 1 1 0 0 > 2 1 2 1 0 > 3 1 3 0 1 > 4 1 4 1 1 > 5 2 5 2 2 > 6 2 6 3 2 > 7 2 7 2 3 > 8 2 8 3 3 > > Obviously, for 2 elements the simple rbind works but I would like a > general solution for arbitrary length lists. Hopefully that is clear. > > Kevin > > -- > Kevin E. Thorpe > Head of Biostatistics, Applied Health Research Centre (AHRC) > Li Ka Shing Knowledge Institute of St. Michael's Hospital > Assistant Professor, Dalla Lana School of Public Health > University of Toronto > email: kevin.thorpe at utoronto.ca Tel: 416.864.5776 Fax: 416.864.3016 > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posti > ng-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Saludos, Carlos Ortega www.qualityexcellence.es [[alternative HTML version deleted]]
I believe that a slightly more efficient way of doing this without leaving base R is: cbind(do.call(rbind,x), set = rep(seq_along(x), vapply(x,nrow,1)) ) Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Fri, Nov 4, 2016 at 5:50 AM, Charles Determan <cdetermanjr at gmail.com> wrote:> Hi Kevin, > > There may be a more elegant way but the following do.call and lapply should > solve your problem. > > do.call(rbind, lapply(seq(length(x)), function(i) data.frame(set=i, > x[[i]]))) > > Regards, > Charles > > On Fri, Nov 4, 2016 at 7:37 AM, Kevin E. Thorpe <kevin.thorpe at utoronto.ca> > wrote: > >> There is probably a very simple elegant way to do this, but I have been >> unable to find it. Here is a toy example. Suppose I have a list of data >> frames like this. >> >> print(x <- list('1'=data.frame(id=1:4,expand.grid(x1=0:1,x2=0:1)),'2'>> data.frame(id=5:8,expand.grid(x1=2:3,x2=2:3)))) >> $`1` >> id x1 x2 >> 1 1 0 0 >> 2 2 1 0 >> 3 3 0 1 >> 4 4 1 1 >> >> $`2` >> id x1 x2 >> 1 5 2 2 >> 2 6 3 2 >> 3 7 2 3 >> 4 8 3 3 >> >> The real application will have more than 2 elements so I'm looking for a >> general approach. I basically want to rbind the data frames in each list >> element and add a variable that adds the element name. In this example the >> result would look something like this. >> >> rbind(data.frame(set='1',x[[1]]),data.frame(set='2',x[[2]])) >> set id x1 x2 >> 1 1 1 0 0 >> 2 1 2 1 0 >> 3 1 3 0 1 >> 4 1 4 1 1 >> 5 2 5 2 2 >> 6 2 6 3 2 >> 7 2 7 2 3 >> 8 2 8 3 3 >> >> Obviously, for 2 elements the simple rbind works but I would like a >> general solution for arbitrary length lists. Hopefully that is clear. >> >> Kevin >> >> -- >> Kevin E. Thorpe >> Head of Biostatistics, Applied Health Research Centre (AHRC) >> Li Ka Shing Knowledge Institute of St. Michael's Hospital >> Assistant Professor, Dalla Lana School of Public Health >> University of Toronto >> email: kevin.thorpe at utoronto.ca Tel: 416.864.5776 Fax: 416.864.3016 >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posti >> ng-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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.