CODEWITHSUNDEEP
arraystype-conversionjulia
Zach
Zach

Reputation: 616

Convert Array{Int, 1} into Array{Int, 2}

I use a function which take an Array{Int, 2} as an argument but it does not work when the array only contains 1 integer (as the array type is Array{Int, 1} in that case).

I know how to create an Array{Int, 2} with 2 or more integers:

S2 = [1 2] # S2 is an Array{Int, 2}
S3 = [1 2 3] # S3 is an Array{Int, 2}

but I don't know how to create an Array{Int, 2} with only 1 integer:

S1 = [1] # S1 is an Array{Int, 1}

Is it possible?

Upvotes: 0

Views: 155

Answers (2)

Bogumił Kamiński
Bogumił Kamiński

Reputation: 69869

Use hcat function, e.g.:

julia> hcat(1)
1×1 Array{Int64,2}:
 1

This also works if you want to convert vector to a matrix:

julia> x = [1]
1-element Array{Int64,1}:
 1

julia> hcat(x)
1×1 Array{Int64,2}:
 1

EDIT: as an afterthought you can also do it like this:

julia> fill(10,1,1)
1×1 Array{Int64,2}:
 10

it is more complex, but this way you can simply create an object of higher dimension e.g.:

julia> fill(10,1,1,1)
1×1×1 Array{Int64,3}:
[:, :, 1] =
 10

EDIT 2: a general solution to put a new dimension of length 1 to any array in any place would be to use a comprehension:

julia> x = [1 2
            3 4]
2×2 Array{Int64,2}:
 1  2
 3  4

julia> [x[i,k] for i in 1:size(x,1), j in 1:1, k in 1:size(x,2)]
2×1×2 Array{Int64,3}:
[:, :, 1] =
 1
 3

[:, :, 2] =
 2
 4

Upvotes: 2

Picaud Vincent
Picaud Vincent

Reputation: 10982

Another possibility is to use reshape

julia> S1 = [1]
1-element Array{Int64,1}:
 1

julia> reshape(S1,1,1)
1×1 Array{Int64,2}:
 1

Upvotes: 3

Related Questions