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Convert a matrix's columns to list

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Convert a matrix's columns to list

Feng Li
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Re: Convert a matrix's columns to list

Henrique Dallazuanna
Try this:

c(unname(as.data.frame(a)))


On Tue, Jan 18, 2011 at 10:53 AM, Feng Li <[hidden email]> wrote:

> Dear R,
>
> Is there an efficient way to make a list that each element is from the
> corresponding column of a matrix. For example, if I have a matrix "a"
>
> > a <- matrix(1:10, 5, 2)
> > a
>     [,1] [,2]
> [1,]    1    6
> [2,]    2    7
> [3,]    3    8
> [4,]    4    9
> [5,]    5   10
>
> I would like to have a list "b" like this
>
> > b <- list(a[, 1], a[, 2])
> > b
> [[1]]
> [1] 1 2 3 4 5
>
> [[2]]
> [1]  6  7  8  9 10
>
>
> Thanks in advance!
>
>
> Feng
>
> --
> Feng Li
> Department of Statistics
> Stockholm University
> 106 91 Stockholm, Sweden
> http://feng.li/
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] 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.
>


--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

        [[alternative HTML version deleted]]


______________________________________________
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Re: Convert a matrix's columns to list

Vito M. R. Muggeo
In reply to this post by Feng Li
hi feng,
a possible solution is

b1<-apply(a,2,list)

and possibly

lapply(b1,unlist)

if you want exactly the output equal to "list(a[, 1], a[, 2])"

best,
vito

Il 18/01/2011 13.53, Feng Li ha scritto:

> Dear R,
>
> Is there an efficient way to make a list that each element is from the
> corresponding column of a matrix. For example, if I have a matrix "a"
>
>> a<- matrix(1:10, 5, 2)
>> a
>       [,1] [,2]
> [1,]    1    6
> [2,]    2    7
> [3,]    3    8
> [4,]    4    9
> [5,]    5   10
>
> I would like to have a list "b" like this
>
>> b<- list(a[, 1], a[, 2])
>> b
> [[1]]
> [1] 1 2 3 4 5
>
> [[2]]
> [1]  6  7  8  9 10
>
>
> Thanks in advance!
>
>
> Feng
>

--
====================================
Vito M.R. Muggeo
Dip.to Sc Statist e Matem `Vianelli'
Università di Palermo
viale delle Scienze, edificio 13
90128 Palermo - ITALY
tel: 091 23895240
fax: 091 485726/485612
http://dssm.unipa.it/vmuggeo

______________________________________________
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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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