How to Directly Define Multidimensional Arrays in Julia
Explanation
1D arrays (vectors) are defined as follows.
julia> A = [1; 2; 3]
3-element Vector{Int64}:
1
2
3
Here, ; signifies moving to the next element based on the first dimension. By generalizing this, ;; signifies moving to the next element based on the second dimension.
julia> A = [1; 2; 3;; 4; 5; 6]
3×2 Matrix{Int64}:
1 4
2 5
3 6
Similarly, arrays of three dimensions and above can be defined. Note that this code is possible from Julia version 1.7 onwards.
julia> A = [1 2; 3 4;;; 5 6; 7 8]
2×2×2 Array{Int64, 3}:
[:, :, 1] =
1 2
3 4
[:, :, 2] =
5 6
7 8
julia> A = [1 2; 3 4;;; 5 6; 7 8 ;;;; 9 10; 11 12;;; 13 14; 15 16]
2×2×2×2 Array{Int64, 4}:
[:, :, 1, 1] =
1 2
3 4
[:, :, 2, 1] =
5 6
7 8
[:, :, 1, 2] =
9 10
11 12
[:, :, 2, 2] =
13 14
Environment
- OS: Windows10
- Version: Julia 1.7.1