[julia-users] Re: Best way to convert Any of vectors into matrix

[Diego Javier Zea]

   
 A =  Any[[1,2],[3,4],[5,6]]
    
    function to_matrix(A::Vector{Any})
        ncol = length(A)
        nrow = length(A[1])
        B = Array( typeof(A[1][1]) , (nrow, ncol) )
        for i in 1:ncol
            for j in 1:nrow
                B[j,i] = A[i][j]
            end
        end
        B
    end
    
    to_matrix(A)


    2x3 Array{Int64,2}:
     1  3  5
     2  4  6

    function use_hcat(A::Vector{Any})
        B = A[1]
        for i=2:length(A)
            B = hcat(B,A[i])
        end
        B
    end
    
    use_hcat(A)


    2x3 Array{Int64,2}:
     1  3  5
     2  4  6

    @time to_matrix(A)
    elapsed time: 1.1926e-5 seconds (504 bytes allocated)

    @time use_hcat(A)
    elapsed time: 8.743e-6 seconds (288 bytes allocated)


El viernes, 22 de agosto de 2014 23:05:19 UTC-3, Bradley Setzler escribió:
>
> Good evening,
>
> I often have Any types filled with vectors (especially as the return of a 
> pmap), and need them as a matrix or DataFrame. For example, suppose I have,
>
> julia> A
> 3-element Array{Any,1}: 
> [1,2] 
> [3,4] 
> [5,6]
>
> But I want,
>
> julia> B
> 2x3 Array{Int64,2}: 
> 1 3 5 
> 2 4 6
>
> I came up with the following, which successfully constructs B from A, but 
> it's a bit inefficient/messy:
>
> B = A[1]
> for i=2:length(A)
>     B = hcat(B,A[i])
> end
>
> Is there a better way to do this? Something like,
> julia> B = hcatForAny(A)
>
> Thanks,
> Bradley
>