Create the matrix with a repeating pattern (R)

Question

There should be a matrix created without a vector. Like a simplified one without entering all the data in the vector.

matrix(c(0, 1, 2, 0, 1, 1, 2, 0, 1, 2, 2, 0, 1, 2, 0, 0, 1, 2, 0, 1, 1, 2, 0, 1, 2), nrow = 5, ncol = 5) 

I've tried:

matrix(0:2, ncol=5, nrow=5)

 > matrix

      [,1] [,2] [,3] [,4] [,5]
 [1,]    0    2    1    0    2
 [2,]    1    0    2    1    0
 [3,]    2    1    0    2    1
 [4,]    0    2    1    0    2
 [5,]    1    0    2    1    0

But it's not helping, as each column should start with the number the previous column ends with.

The final matrix should look like:

> matrix
      [,1] [,2] [,3] [,4] [,5]
 [1,]    0    1    2    0    1
 [2,]    1    2    0    1    2
 [3,]    2    0    1    2    0
 [4,]    0    1    2    0    1
 [5,]    1    2    0    1    2

Answer 1

You can use the index numbers of the rows and columns, and combine the value with the modulo operator %% like this:

n = 5
mat <- matrix(nrow = n, ncol = n)
mat <- (row(mat) + col(mat) + 1) %% 3

> mat
      [,1] [,2] [,3] [,4] [,5] 
[1,]    0    1    2    0    1
[2,]    1    2    0    1    2
[3,]    2    0    1    2    0
[4,]    0    1    2    0    1
[5,]    1    2    0    1    2

Answer 2

mat <- matrix(0:2, nrow = 7, ncol = 5)

> mat
    [,1] [,2] [,3] [,4] [,5]
[1,]    0    1    2    0    1
[2,]    1    2    0    1    2
[3,]    2    0    1    2    0
[4,]    0    1    2    0    1
[5,]    1    2    0    1    2
[6,]    2    0    1    2    0
[7,]    0    1    2    0    1

mat2 <- mat[-6:-7, ]

> mat2
      [,1] [,2] [,3] [,4] [,5]
 [1,]    0    1    2    0    1
 [2,]    1    2    0    1    2
 [3,]    2    0    1    2    0
 [4,]    0    1    2    0    1
 [5,]    1    2    0    1    2