[R] Converting a list to a data frame

[Bill Poling]

Oh, how funny, hence the term Novice usR. UGH!

Thank you Sir.

WHP



From: Kevin E. Thorpe [mailto:kevin.thorpe using utoronto.ca]
Sent: Friday, May 04, 2018 9:08 AM
To: Bill Poling <Bill.Poling using zelis.com>; Huzefa Khalil <huzefa.khalil using umich.edu>
Cc: R Help Mailing List <r-help using r-project.org>
Subject: Re: [R] Converting a list to a data frame

It looks like you made a copy/paste error below. Your ata.frame should
be data.frame.

Kevin

On 05/04/2018 08:18 AM, Bill Poling wrote:
> 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<http://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<http://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 using r-project.org] *On Behalf Of
> *Huzefa Khalil
> *Sent:* Wednesday, May 02, 2018 1:24 PM
> *To:* Kevin E. Thorpe <kevin.thorpe using utoronto.ca<mailto:kevin.thorpe using utoronto.ca>>
> *Cc:* R Help Mailing List <r-help using r-project.org<mailto:r-help using 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<http://do.call>(rbind, temp)
>
>
>
> On Wed, May 2, 2018 at 1:11 PM, Kevin E. Thorpe
> <kevin.thorpe using utoronto.ca <mailto:kevin.thorpe using utoronto.ca<mailto:kevin.thorpe using utoronto.ca%20%3cmailto:kevin.thorpe using 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 using utoronto.ca<mailto:kevin.thorpe using utoronto.ca> <mailto:kevin.thorpe using utoronto.ca>
> Tel: 416.864.5776 Fax: 416.864.3016


--
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<mailto:kevin.thorpe using utoronto.ca> Tel: 416.864.5776 Fax: 416.864.3016

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