[R] Converting a list to a data frame

Huzefa Khalil huze|@@kh@||| @end|ng |rom um|ch@edu
Wed May 2 19:23:54 CEST 2018

Hi Kevin,

There is probably a better way, but it can be done in two steps like this

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

temp <- lapply(names(temp), function(n, temp) {
  temp[[n]]$type <- n
}, temp = temp)

do.call(rbind, temp)

On Wed, May 2, 2018 at 1:11 PM, Kevin E. Thorpe <kevin.thorpe using utoronto.ca>

> 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 using utoronto.ca  Tel: 416.864.5776  Fax: 416.864.3016
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