在Julia中连接数组

Question

如果这两个Int数组是,a = [1;2;3]并且b = [4;5;6],我们如何在两个维度中连接两个数组？预期的产出是,

julia> out1
6-element Array{Int64,1}:
 1
 2
 3
 4
 5
 6

julia> out2
3x2 Array{Int64,2}:
 1  4
 2  5
 3  6

Answer 1

使用vcat和hcat功能:

julia> a, b = [1;2;3], [4;5;6]
([1,2,3],[4,5,6])

help?> vcat
Base.vcat(A...)

   Concatenate along dimension 1

julia> vcat(a, b)
6-element Array{Int64,1}:
 1
 2
 3
 4
 5
 6

help?> hcat
Base.hcat(A...)

   Concatenate along dimension 2

julia> hcat(a, b)
3x2 Array{Int64,2}:
 1  4
 2  5
 3  6

Answer 2

方括号可用于连接:

julia> a, b = [1;2;3], [4;5;6]
([1,2,3],[4,5,6])

julia> [a; b]
6-element Array{Int64,1}:
 1
 2
 3
 4
 5
 6

julia> [a b]
3×2 Array{Int64,2}:
 1  4
 2  5
 3  6

Answer 3

您可以使用该cat函数沿任何维度连接任意数量的数组.第一个输入是执行连接的维度; 其余输入是您希望连接在一起的所有数组

a = [1;2;3]
b = [4;5;6]

## Concatenate 2 arrays along the first dimension
cat(1,a,b)
6-element Array{Int64,1}:
 1
 2
 3
 4
 5
 6

## Concatenate 2 arrays along the second dimension
cat(2,a,b)
3x2 Array{Int64,2}:
 1  4
 2  5
 3  6

## Concatenate 2 arrays along the third dimension
cat(3,a,b)
3x1x2 Array{Int64,3}:
[:, :, 1] =
 1
 2
 3

[:, :, 2] =
 4
 5
 6