[R] Converting a list to a matrix - I still don't think I have itright

[Dimitris Rizopoulos]

mat <- matrix(unlist(l2), nrow=length(l2), byrow=TRUE)
rownames(mat) <- names(l2)
mat

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "michael watson (IAH-C)" <michael.watson at bbsrc.ac.uk>
To: <r-help at r-project.org>
Sent: Thursday, February 17, 2005 3:36 PM
Subject: [R] Converting a list to a matrix - I still don't think I 
have itright


> Hi
>
> We have touched on this before, but I don't think I quite got it 
> right.
>
> So I have a list, each element of which is a a vector of 2 numbers:
>
>> l2
> $cat000_a01
> [1] 0.3429944 4.5138244
>
> $cat000_a02
> [1] 0.1929336 4.3064944
>
> $cat000_a03
> [1] -0.2607796  4.1551591
>
> What I actually want to convert this into is a matrix with the names
> (cat000_a01 etc) as row names, the first element of each of the 
> vectors
> forming the first column of the new matrix, and the second element 
> of
> each of the vectors forming the second column:
>
> cat000_a01 0.3429944 4.5138244
> cat000_a02 0.1929336 4.3064944
> cat000_a03 -0.2607796  4.1551591
>
> What was suggested on the list last time was
> matrix(unlist(mylist),nrow=length(mylist)).  But if I do this I get:
>
>> matrix(unlist(l2),nrow=length(l2))
>          [,1]       [,2]
> [1,] 0.3429944  4.3064944
> [2,] 4.5138244 -0.2607796
> [3,] 0.1929336  4.1551591
>
> Which is not what I want.  Here, the second element of the first 
> vector
> in my list has gone into the first column of the new matrix, and 
> that's
> not what I want at all.
>
> Any more help would be appreciated.
>
> Thanks
> Mick
>
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