Language Julia: convert vector in matrix

Question

Who can help.

To transform a vector into a one-dimensional matrix just run in Julia:

a = copy(permutedims([1,2,3]))

To transform the matrix "a" into a vector just use:

b = copy(vec(a))

If you have a matrix "[1 2 3; 4 5 6]" to transform it into a vector, just:

c = vec([1 2 3; 4 5 6])

Now how to make the vector have the form of the 2x3 matrix like:

2×3 Matrix{Int64}:
 1  2  3
 4  5  6

Answer 1

You can use reshape

julia> c = vec([1 2 3; 4 5 6])
6-element Vector{Int64}:
 1
 4
 2
 5
 3
 6

julia> M=reshape(c,2,3)
2×3 Matrix{Int64}:
 1  2  3
 4  5  6

Note that this operation does not reallocate memory, c and M share the same memory. By example:

julia> c[1]=10
10

julia> M
2×3 Matrix{Int64}:
 10  2  3
  4  5  6