Converting a list to a data frame

Typo: dat[[z]] should be x[[z]]:

x2 <- do.call(rbind, lapply(names(x), function(z) 
      data.frame(type=z, x[[z]])))
x2
  type x y
1    A 1 3
2    A 2 4
3    B 5 7
4    B 6 8

David C

-----Original Message-----
From: R-help <r-help-bounces at r-project.org> On Behalf Of David L Carlson
Sent: Wednesday, May 2, 2018 3:51 PM
To: William Dunlap <wdunlap at tibco.com>; Kevin E. Thorpe <kevin.thorpe at utoronto.ca>
Cc: r-help mailing list <r-help at r-project.org>
Subject: Re: [R] Converting a list to a data frame

Or add the type column first and then rbind:

x <- list(A=data.frame(x=1:2, y=3:4),B=data.frame(x=5:6,y=7:8))
x2 <- do.call(rbind, lapply(names(x), function(z) 
      data.frame(type=z, dat[[z]])))

----------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77843-4352

-----Original Message-----
From: R-help <r-help-bounces at r-project.org> On Behalf Of William Dunlap via R-help
Sent: Wednesday, May 2, 2018 12:28 PM
To: Kevin E. Thorpe <kevin.thorpe at utoronto.ca>
Cc: R Help Mailing List <r-help at r-project.org>
Subject: Re: [R] Converting a list to a data frame

x1 <- do.call(rbind, c(x, list(make.row.names=FALSE)))
x2 <- cbind(type=rep(names(x), vapply(x, nrow, 0)), x1)
str(x2)

'data.frame':   4 obs. of  3 variables:
 $ type: Factor w/ 2 levels "A","B": 1 1 2 2
 $ x   : int  1 2 5 6
 $ y   : int  3 4 7 8


Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, May 2, 2018 at 10:11 AM, Kevin E. Thorpe <kevin.thorpe at utoronto.ca>
wrote:

I suspect this is pretty easy, but I'm having trouble figuring it out.
Basically, I have a list of data frames such as the following example:

list(A=data.frame(x=1:2, y=3:4),B=data.frame(x=5:6,y=7:8))

I would like to turn this into  data frame where the list elements are 
essentially rbind'ed together and the element name becomes a new variable.
For example, I would like to turn the list above into a data frame 
that looks like this:

data.frame(type=c("A","A","B","B"),x=c(1:2,5:6),y=c(3:4,7:8))

Appreciate any pointers.

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

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______________________________________________
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.