Just curious: if it was [true,true,false] or [false,true,true] would it
then be possible? The memory for a matrix is still inline, so these cases
should correspond to changing the dimensions or rebasing the initial
column.
On Tuesday, September 8, 2015 at 4:10:07 AM UTC+10, Tomas Lycken wrote:
>
> No, that's not possible, at least not in general - to do that, you would
> have to at least shift all the elements of the columns after the deleted
> one to make the matrix memory layout consistent.
>
> What you can do, if you don't need to use the matrix as an actual matrix,
> is to use e.g. a Vector{Vector{Float64}} instead of a Matrix{Float64}. That
> gives you a vector of columns with which you can add and delete columns at
> will. However, it will be much more expensive to address this data
> structure by rows, since you will lose cache-locality.
>
> // T
>
> On Sunday, September 6, 2015 at 11:29:39 PM UTC+2, Diego Javier Zea wrote:
>>
>> Is there some function for deleting columns in-place? I want to do
>> something like the next, but changing the matrix in-place.
>>
>> julia> mat = [ 1 2 3
>> 4 5 6 ]
>> 2x3 Array{Int64,2}:
>> 1 2 3
>> 4 5 6
>>
>> julia> mat[:, [true, false, true]]
>> 2x2 Array{Int64,2}:
>> 1 3
>> 4 6
>>
>>
>> Thanks in advance!
>>
>
