How to unlist a list of matrix elements and get combination of matrix as output instead of as vector in R

Question

If I have a list called List A:

[[1]]
  [1] 11.000000  1.500000  2.666667  2.833333 10.000000  1.500000

[[2]]
  [1]  1.50  1.00  3.25  3.75 10.50  1.50

[[3]]
  [1] 10.5  1.5  1.5  1.5  5.0  5.5

How can I unlist List A in R and get the output as per below:

         [,1]       [,2]      [,3]      [,4]     [,5]      [,6]
  [,1] 11.000000  1.500000  2.666667  2.833333 10.000000  1.500000
  [,2] 1.50       1.00      3.25      3.75     10.50      1.50
  [,3] 10.5       1.5       1.5       1.5      5.0        5.5

If I simply use unlist() it returns a vector

score 7 · Accepted Answer · answered Jan 15 '18 at 06:55

7

We can use do.call with rbind

do.call(rbind, A)

answered Jan 15 '18 at 06:55

akrun

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Hi thank you so much for the solution – DataMiningStudent Jan 15 '18 at 07:14

score 4 · Answer 2 · answered Jan 15 '18 at 07:06

4

akrun's answer works well. An alternative method, which utilizes unlist(), is:

matrix(unlist(A), ncol=6, byrow=T)

This converts A into a vector, and then reorganizes it into a matrix with 6 columns, with the elements sorted by row.

answered Jan 15 '18 at 07:06

MBorg

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Hi thank you so much for the alternative method – DataMiningStudent Jan 15 '18 at 07:13

score 2 · Answer 3 · answered Jan 15 '18 at 07:19

2

Also, invoke from purrr:

purrr::invoke(rbind, A)

invoke is just a wrapper around do.call.

answered Jan 15 '18 at 07:19

tyluRp

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Hi thank you for the solution – DataMiningStudent Jan 15 '18 at 07:31

How to unlist a list of matrix elements and get combination of matrix as output instead of as vector in R

3 Answers3