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David L Carlson

2018-May-02 20:50 UTC

[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
>
> ______________________________________________
> 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.

David L Carlson

2018-May-02 21:43 UTC

head link

[R] 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
>
> ______________________________________________
> 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.

______________________________________________
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.

Martin Maechler

2018-May-03 07:59 UTC

head link

[R] Converting a list to a data frame

>>>>> David L Carlson <dcarlson at tamu.edu>
>>>>>     on Wed, 2 May 2018 21:43:52 +0000 writes:
> 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
Before this thread gets carried away to data.table and
tibbleverse (and as nobody else has done so) :

Let me nominate this beautiful solution by
Bill Dunlap and David Carlson to win the prize  with a 10 out 10 grade:

Beautiful use of  do.call() and lapply(), two of the most
versatile and important functions from the base R toolbox.

Congratulations!

Martin Maechler
R Core Team

> -----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
> >
> ______________________________________________
> 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.

David Winsemius

2018-May-03 16:32 UTC

head link

[R] Converting a list to a data frame

> On May 2, 2018, at 2:43 PM, David L Carlson <dcarlson at tamu.edu>
wrote:
> 
> 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
Sometimes one want to "bind" list that have some columns in common and
others that you want to include from one but leave as NA for the rows from the
other. The rbind.list function from package-plyr is from the pre-tidy/tibble era
of Hadley's efforts and provides that facility out of the box. It also seems
to "work" with the do.call(rbind strategy for named lists above.

x <- list(A=mtcars[c("mpg", "wt")] ,
B=mtcars[c("wt", "cyl")])  #mtcars
x2 <- do.call(rbind.fill, lapply(names(x), function(z) 
     data.frame(type=z, x[[z]])))
str(x2)
#---------
'data.frame':	64 obs. of  4 variables:
 type: Factor w/ 2 levels "A","B": 1 1 1 1 1 1 1 1 1 1 ...
 mpg : num  21 21 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 ...
 wt  : num  2.62 2.88 2.32 3.21 3.44 ...
 cyl : num  NA NA NA NA NA NA NA NA NA NA ...

-- 
David, the other.
> 
> 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
>> 
>> ______________________________________________
>> 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.
> 
> ______________________________________________
> 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.
> 
> ______________________________________________
> 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.
David Winsemius
Alameda, CA, USA

'Any technology distinguishable from magic is insufficiently advanced.' 
-Gehm's Corollary to Clarke's Third Law

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