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How to convert an array into a matrix in R?
To convert an array into a matrix in R, we can use apply function. For example, if we have an array called ARRAY that contains 2 array elements then we can convert this array into a single matrix using the command apply(ARRAY,2,c). We need to understand the dimension of the array making the conversion otherwise the output will not be as expected.
Example
Consider the below array −
x1<-array(1:50,dim=c(5,5,2)) x1 , , 1
Output
[,1] [,2] [,3] [,4] [,5] [1,] 1 6 11 16 21 [2,] 2 7 12 17 22 [3,] 3 8 13 18 23 [4,] 4 9 14 19 24 [5,] 5 10 15 20 25 , , 2 [,1] [,2] [,3] [,4] [,5] [1,] 26 31 36 41 46 [2,] 27 32 37 42 47 [3,] 28 33 38 43 48 [4,] 29 34 39 44 49 [5,] 30 35 40 45 50
Converting x1 into a matrix −
Example
apply(x1,2,c)
Output
[,1] [,2] [,3] [,4] [,5] [1,] 1 6 11 16 21 [2,] 2 7 12 17 22 [3,] 3 8 13 18 23 [4,] 4 9 14 19 24 [5,] 5 10 15 20 25 [6,] 26 31 36 41 46 [7,] 27 32 37 42 47 [8,] 28 33 38 43 48 [9,] 29 34 39 44 49 [10,] 30 35 40 45 50
Example
x2<-array(rpois(20,5),dim=c(10,2,2)) x2
Output
, , 1 [,1] [,2] [1,] 8 7 [2,] 8 9 [3,] 6 6 [4,] 5 5 [5,] 5 6 [6,] 5 7 [7,] 1 3 [8,] 8 7 [9,] 6 3 [10,] 3 2 , , 2 [,1] [,2] [1,] 8 7 [2,] 8 9 [3,] 6 6 [4,] 5 5 [5,] 5 6 [6,] 5 7 [7,] 1 3 [8,] 8 7 [9,] 6 3 [10,] 3 2
Converting x2 into a matrix −
Example
apply(x2,2,c)
Output
[,1] [,2] [1,] 8 7 [2,] 8 9 [3,] 6 6 [4,] 5 5 [5,] 5 6 [6,] 5 7 [7,] 1 3 [8,] 8 7 [9,] 6 3 [10,] 3 2 [11,] 8 7 [12,] 8 9 [13,] 6 6 [14,] 5 5 [15,] 5 6 [16,] 5 7 [17,] 1 3 [18,] 8 7 [19,] 6 3 [20,] 3 2
Updated on: 17-Mar-2021
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