[R] Adding objects to a list

David Winsemius dwinsemius at comcast.net
Mon Jun 20 11:35:04 CEST 2011


On Jun 20, 2011, at 5:00 AM, mdvaan wrote:

> #Hi list,
>
> #From the code below I get two list objects (n$values and n$vectors):

One of which is a numeric vector and the other of which is a matrix.
> dat <- matrix(1:9,3)
> n<-eigen(dat)
> n
>
> # How do I add another object to n that replicates n$vectors and is  
> called
> n$vectors$test?
> # Thanks a lot!

Maybe you should explain what your goal is. At the moment n$vectors is  
not a list but rather a matrix. As such assignment of <anything> to n 
$vectors$test will result in coercion of the matrix elements to  
individual list elements, as you should have seen from the warning  
message when you tried the obvious.

 > n$vectors$test <- n$vectors
Warning message:
In n$vectors$test <- n$vectors : Coercing LHS to a list

 > n
$values
[1]  1.611684e+01 -1.116844e+00 -5.700691e-16

$vectors
$vectors[[1]]
[1] -0.4645473

$vectors[[2]]
[1] -0.5707955

$vectors[[3]]
[1] -0.6770438

$vectors[[4]]
[1] -0.882906

$vectors[[5]]
[1] -0.2395204

$vectors[[6]]
[1] 0.4038651

$vectors[[7]]
[1] 0.4082483

$vectors[[8]]
[1] -0.8164966

$vectors[[9]]
[1] 0.4082483

$vectors$test
            [,1]       [,2]       [,3]
[1,] -0.4645473 -0.8829060  0.4082483
[2,] -0.5707955 -0.2395204 -0.8164966
[3,] -0.6770438  0.4038651  0.4082483

So the tenth element of n$vectors (which is now of a different class)  
will be the desired result but you have 9 list elements that were the  
original matrix values

 > n$vectors[[10]]
            [,1]       [,2]       [,3]
[1,] -0.4645473 -0.8829060  0.4082483
[2,] -0.5707955 -0.2395204 -0.8164966
[3,] -0.6770438  0.4038651  0.4082483

>
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>
> --
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>
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David Winsemius, MD
West Hartford, CT



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