[R] Indexing a loop-created list

[Nicolas Prune]

Hello,

I create a certain number (n*m) matrices, that I would like to store. These
matrices have different dimensions. As far as I know, for matrices of different
dimensions, there's no alternative to a list.

Here's how I store them on the fly :

my_list - NULL

for (i in 1:n)
{for (j in (i+1):m)
{my_list - list(my_list,i_create_a_matrix(i,j)))
}
}

But the indexation of the result is horrible ! (see below a simplified version,
with no matrices created but i*10+j added to the list instead). Is there a
cleaner way to get the same result ?

Any help will be very welcomed.
Nicolas

[[1]]
[[1]][[1]]
[[1]][[1]][[1]]
[[1]][[1]][[1]][[1]]
[[1]][[1]][[1]][[1]][[1]]
[[1]][[1]][[1]][[1]][[1]][[1]]
NULL

[[1]][[1]][[1]][[1]][[1]][[2]]
[1] 12


[[1]][[1]][[1]][[1]][[2]]
[1] 13


[[1]][[1]][[1]][[2]]
[1] 14


[[1]][[1]][[2]]
[1] 23


[[1]][[2]]
[1] 24


[[2]]
[1] 34

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Re: [R] Indexing a loop-created list

[Romain Lorrilliere]

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Re: [R] Indexing a loop-created list

[Romain Lorrilliere]

  hi,

 try this:

 my_list - NULL

 for (i in 1:n)
   {for (j in (i+1):m)
   {my_list - c(my_list,list(i_create_a_matrix(i,j)))
   }
 }

   

 Best,

 Romain


 Romain Lorrillière

  

 UMR 8079 Laboratoire Ecologie, Systématique et Evolution

 Bât. 362

 Université Paris-Sud

 91405 Orsay cedex

 France

  

 tel : 01 69 15 56 85

 fax : 01 69 15 56 96

 mobile : 06 81 70 90 70

  

 email : [EMAIL PROTECTED]

  



 Nicolas Prune a écrit :
 Hello,

 I create a certain number (n*m) matrices, that I would like to store. These
 matrices have different dimensions. As far as I know, for matrices of 
 different
 dimensions, there's no alternative to a list.

 Here's how I store them on the fly :

 my_list - NULL

 for (i in 1:n)
  {for (j in (i+1):m)
  {my_list - list(my_list,i_create_a_matrix(i,j)))
  }
 }

 But the indexation of the result is horrible ! (see below a simplified 
 version,
 with no matrices created but i*10+j added to the list instead). Is there a
 cleaner way to get the same result ?

 Any help will be very welcomed.
 Nicolas

 [[1]]
 [[1]][[1]]
 [[1]][[1]][[1]]
 [[1]][[1]][[1]][[1]]
 [[1]][[1]][[1]][[1]][[1]]
 [[1]][[1]][[1]][[1]][[1]][[1]]
 NULL

 [[1]][[1]][[1]][[1]][[1]][[2]]
 [1] 12


 [[1]][[1]][[1]][[1]][[2]]
 [1] 13


 [[1]][[1]][[1]][[2]]
 [1] 14


 [[1]][[1]][[2]]
 [1] 23


 [[1]][[2]]
 [1] 24


 [[2]]
 [1] 34

 __
 R-help@stat.math.ethz.ch 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.




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and provide commented, minimal, self-contained, reproducible code.

Re: [R] Indexing a loop-created list

[Richard M. Heiberger]

m - 2
n - 3

matlist - matrix(vector(list), m, n)

for (i in 1:m)
  for (j in 1:n)
matlist[[i,j]] - matrix(sample(12), 3, 4)

matlist[[1,2]] ## access with double[[ subscripts

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Re: [R] Indexing a loop-created list

[Alberto Monteiro]

Romain Lorrilliere wrote:

 try this:

 my_list - NULL

 for (i in 1:n)
   {for (j in (i+1):m)
   {my_list - c(my_list,list(i_create_a_matrix(i,j)))
   }
 }

Why it does not work as expected in this case?

  my_list - NULL

  for (i in 1:10)
my_list - c(my_list, function(x) x^i)

  f - my_list[[2]]
  f(10)

[1] 1e+10

Alberto Monteiro

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