[R] Converting a list to a data frame

Bill Poling
Fri, 04 May 2018 12:18:32 -0000

Good morning.

Novice usR. Here.

I am following this string, among many, learning as I go.

Quick question please?

I thought that perhaps ata.frame was part of the zoo pkg, b/c when I searched it
came up in help?

However, evidently not or I am not using it properly.

Please advise, thank you.
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)
ata.frame(type=z, dat[[z]])))
#Error in ata.frame(type = z, dat[[z]]) : could not find function
"ata.frame"

?ata.frame
??ata.frame #Looks like it's part of the zoo package?
install.packages("zoo")

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

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)
ata.frame(type=z, x[[z]])))
#Error in ata.frame(type = z, dat[[z]]) : still cannot find function
"ata.frame"?

William H. Poling, Ph.D.

From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Huzefa Khalil
Sent: Wednesday, May 02, 2018 1:24 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

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
return(temp[[n]])
}, temp = temp)

do.call(rbind, temp)



On Wed, May 2, 2018 at 1:11 PM, Kevin E. Thorpe <kevin.thorpe at
utoronto.ca<mailto: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<mailto:kevin.thorpe at
utoronto.ca> Tel: 416.864.5776 Fax: 416.864.3016
>
> ______________________________________________
> R-help at r-project.org<mailto:R-help at r-project.org> mailing list
-- To UNSUBSCRIBE and more, see
>
https://stat.ethz.ch/mailman/listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
> PLEASE do read the posting guide
http://www.R-project.org/posti<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<mailto:R-help at r-project.org> mailing list -- To
UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html<http://www.R-project.org/posting-guide.html>
and provide commented, minimal, self-contained, reproducible code.

Confidentiality Notice This message is sent from Zelis. ...{{dropped:15}}