[R] List to matrix or to vectors conversion

[(Ted Harding)]

On 12-Feb-10 13:14:29, Juan Tomas Sayago wrote:
> Dear list,
> I have a list with 1000 x1000 lines and columns do you know how I can
> convert it to matrrix or data.frame.
> Thanks.
> Juan

as.data.frame() will convert it to a dataframe. If you then apply
as.matrix() to the result you will get a matrix:

  L <- list(X=c(1,2,3),Y=c(4,5,6),Z=c(7,8,9))
  L
  # $X
  # [1] 1 2 3
  # $Y
  # [1] 4 5 6
  # $Z
  # [1] 7 8 9

  D <- as.data.frame(L)
  D
  #   X Y Z
  # 1 1 4 7
  # 2 2 5 8
  # 3 3 6 9

  M <- as.matrix(D)
  M
  #      X Y Z
  # [1,] 1 4 7
  # [2,] 2 5 8
  # [3,] 3 6 9

Note that applying as.matrix() directly to the original L will
not work. It returns a list, not a matrix.

Ted.

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E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
Fax-to-email: +44 (0)870 094 0861
Date: 12-Feb-10                                       Time: 13:40:32
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