Julia Arrays

Julia supports single- and multi-dimensional arrays.

Declaration

A single-dimensional array is called a vector.

julia> [1,2,3]
3-element Vector{Int64}:
 1
 2
 3

Arrays take the common type of all their elements. If the elements are not of the same type but have a common promotion type, the elements are recast.

julia> [1, 2.3, 4//5]
3-element Vector{Float64}:
 1.0
 2.3
 0.8

Elements can also be explicitly recast at declaration of an array.

julia> Float32[1, 2.3, 4//5]
3-element Vector{Float32}:
 1.0
 2.3
 0.8

If elements are delimited by single semicolons (;) or newlines, they are vertically concatenated. This usually still results in a vector.

julia> [1:2; 4:5]
4-element Vector{Int64}:
 1
 2
 4
 5

julia> [1:2
        4:5
        6]
5-element Vector{Int64}:
 1
 2
 4
 5
 6

If elements are delimited by tabs or spaces or double semicolons, they are horizontally concatenated. This usually creates a matrix, a multi-dimensional array.

julia> [1:2  4:5  7:8]
2×3 Matrix{Int64}:
 1  4  7
 2  5  8

julia> [1 2 3]
1×3 Matrix{Int64}:
 1  2  3

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