R help - Apr 2020 - create a r list from dataframe using the first column as list names

Hello allI need to create a r list with each row as a list object and named with
the element in the first column.? Illustrated below:> a<-
as.data.frame(matrix(LETTERS[1:16],nrow = 4))> a? V1 V2 V3 V41 ?A ?E ?I ?M2
?B ?F ?J ?N3 ?C ?G ?K ?O4 ?D ?H ?L ?P
I want the list looks like$A[1] E I MLevels: E I M
$B[1] F J NLevels: F J N
$C[1] G K OLevels: G K O
$D[1] H L PLevels: H L P

I used the script below, it does not work the way I wantlapply(split(a,a$V1),
function(x) as.list(a[-1]))?
any help would be greatly appreciated!
Anna
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On 2020-04-09 15:00 +0000, aiguo li via R-help wrote:
| Hello allI need to create a r list with 
| each row as a list object and named with 
| the element in the first column.? 

Dear aiguo,

Perhaps this fits your bill?

  a <- matrix(LETTERS[1:16], nrow = 4)
  FUN <- function(x) { as.factor(x[-1]) }
  lapply(X=split(a, a[,1]), FUN=FUN)

Best,
Rasmus

Hello,

Your post is unreadable, please repost in *plain text*, not HTML.

Rui Barradas

?s 16:00 de 09/04/20, aiguo li via R-help escreveu:
> Hello allI need to create a r list with each row as a list object and named
with the element in the first column.? Illustrated below:> a<-
as.data.frame(matrix(LETTERS[1:16],nrow = 4))> a? V1 V2 V3 V41 ?A ?E ?I ?M2
?B ?F ?J ?N3 ?C ?G ?K ?O4 ?D ?H ?L ?P
> I want the list looks like$A[1] E I MLevels: E I M
> $B[1] F J NLevels: F J N
> $C[1] G K OLevels: G K O
> $D[1] H L PLevels: H L P
> 
> I used the script below, it does not work the way I
wantlapply(split(a,a$V1), function(x) as.list(a[-1]))
> any help would be greatly appreciated!
> Anna
> 	[[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.
>

On 2020-04-09 18:50 +0100, Rui Barradas wrote:
| Hello,
| 
| Your post is unreadable, please repost in 
| *plain text*, not HTML.

Hi!  It was not so bad?  I was able to 
extract out the core parts at least to 
prepare an answer ... maybe a bit hard with 
no line breaks, but ... 

Best,
Rasmus

On 2020-04-09 18:00 +0000, aiguo li wrote:
| That is awesome!  Thanks.

I'm glad this was helpful for you!

On 2020-04-09 18:00 +0000, aiguo li wrote:
| That is awesome!  Thanks.

Dear AiGuo,

I thought: why make this overly 
complicated, when this is also 
possible:

  a <- matrix(LETTERS[1:16], nrow=4)
  X <- split(x=a[,-1], f=a[,1])
  lapply(X=X, FUN=as.factor)

Best,
Rasmus

"I thought: why make this overly complicated,..."

Indeed, though "complicated" is in the eyes of the beholder.
One wonders whether any of this is necessary, though: see ?apply , as in
apply(a, 1, whatever...)
to do things rowwise.

Cheers,
Bert

Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Fri, Apr 10, 2020 at 9:14 AM Rasmus Liland <jensrasmus at gmail.com>
wrote:
> On 2020-04-09 18:00 +0000, aiguo li wrote:
> | That is awesome!  Thanks.
>
> Dear AiGuo,
>
> I thought: why make this overly
> complicated, when this is also
> possible:
>
>   a <- matrix(LETTERS[1:16], nrow=4)
>   X <- split(x=a[,-1], f=a[,1])
>   lapply(X=X, FUN=as.factor)
>
> Best,
> Rasmus
>
> ______________________________________________
> 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.
>
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