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How to get names of a list into df:s?

7 messages · Lauri Nikkinen, Henrique Dallazuanna, Martin Elff +3 more

Original
Lauri Nikkinen
# 
R users,

I have a simple lapply question.

g <- list(a=1:3, b=4:6, c=7:9)
g <- lapply(g, function(x) as.data.frame(x))
lapply(g, function(x) cbind(x, var1 = rep(names(g), each=nrow(x))[1:nrow(x)]))

I get

$a
  x var1
1 1    a
2 2    a
3 3    a

$b
  x var1
1 4    a
2 5    a
3 6    a

$c
  x var1
1 7    a
2 8    a
3 9    a

And I would like to have

$a
  x var1
1 1    a
2 2    a
3 3    a

$b
  x var1
1 4    b
2 5    b
3 6    b

$c
  x var1
1 7    c
2 8    c
3 9    c

How should I modify my lapply clause to achieve this?

Best regards,
Lauri
R version 2.6.1 (2007-11-26)
i386-apple-darwin8.10.1

locale:
C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base
Henrique Dallazuanna
# 
Try this:

g <- list(a=1:3, b=4:6, c=7:9)
with(stack(g), split(stack(g), ind))
On 21/02/2008, Lauri Nikkinen <lauri.nikkinen at iki.fi> wrote:

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Martin Elff
    

    

      
      #
    

  


  

      
On Thursday 21 February 2008 (19:22:40), Lauri Nikkinen wrote:

            

      
      
      
    

        
The following seems to work:

sapply(names(g), 
	function(n) 
		cbind(
			g[[n]], 
			var1 = rep(n,each=nrow(g[[n]]))
		),
		simplify=FALSE)



Best,
Martin

  
  


  


      

    

    

      
      

        


  

        

      John Kane
    

    

      
      #
    

  


  

      
I don't see any difference

        
--- Lauri Nikkinen <lauri.nikkinen at iki.fi> wrote:

        

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Bert Gunter
    

    

      
      #
    

  


  

      
mapply(data.frame,value=g,nm=lapply(names(g),rep,length(g)),SIMPLIFY=FALSE)

Cheers,

Bert Gunter
Genentech

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of John Kane
Sent: Thursday, February 21, 2008 2:05 PM
To: Lauri Nikkinen; r-help at stat.math.ethz.ch
Subject: Re: [R] How to get names of a list into df:s?

I don't see any difference

        
--- Lauri Nikkinen <lauri.nikkinen at iki.fi> wrote:

        

            

      
      
      
    

        

      
      
    

        
______________________________________________
R-help at r-project.org mailing list
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.

  
  


  


      

    

    

      
      

        


  

        

      jim holtman
    

    

      
      #
    

  


  

      
Here is one way of doing it:

            

      
      
      
    

        
[[1]]
  x var1
1 1    a
2 2    a
3 3    a

[[2]]
  x var1
1 4    b
2 5    b
3 6    b

[[3]]
  x var1
1 7    c
2 8    c
3 9    c

        
On Thu, Feb 21, 2008 at 1:22 PM, Lauri Nikkinen <lauri.nikkinen at iki.fi> wrote:

            

      
      
      
    

        

      
      
    

        

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Bert Gunter
    

    

      
      #
    

  


  

      
Jim's solution showed me that mine should be simplified to:

mapply(data.frame,value=g,nm=names(g),SIMPLIFY=FALSE)

This has the slight advantage of automatically naming the list.

Cheers,
Bert Gunter

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of jim holtman
Sent: Thursday, February 21, 2008 4:53 PM
To: Lauri Nikkinen
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] How to get names of a list into df:s?

Here is one way of doing it:

            

      
      
      
    

        
[[1]]
  x var1
1 1    a
2 2    a
3 3    a

[[2]]
  x var1
1 4    b
2 5    b
3 6    b

[[3]]
  x var1
1 7    c
2 8    c
3 9    c


On Thu, Feb 21, 2008 at 1:22 PM, Lauri Nikkinen <lauri.nikkinen at iki.fi>
wrote:

            

      
      
      
    

        
each=nrow(x))[1:nrow(x)]))

            

      
      
      
    

        

      
      
    

        
http://www.R-project.org/posting-guide.html