Thank you very much Matt. In fact I will work with floats, but the idea to
concatenate 2 columns is good !
Le mardi 12 avril 2016 16:58:21 UTC+2, Matt Bauman a écrit :
>
> It'd probably be fastest if you can pre-allocate your array:
>
> A = Array(ASCIIString, 3, 2)
> for i=1:size(A, 1)
> A[i, 1] = string('w'+i, 1)
> A[i, 2] = string('w'+i, 2)
> end
>
> If you don't know how many elements you'll have, you can use two column
> vectors, `c1` and `c2`, and push to them independently. Then horizontally
> concatenate them together to get your resulting `A = [c1 c2]`.
>
> On Tuesday, April 12, 2016 at 10:38:41 AM UTC-4, Fred wrote:
>>
>> Thank you very much Tim !
>>
>> In fact I want to create an X,Y array so if I create a 1D array, I can
>> only append to it (x1,y1) then (x2,y2)... (xn, yn), because I calculate x1
>> before x2...
>>
>> julia> d = ["x1", "y1", "x2", "y2", "x3", "y3"]
>> 6-element Array{ASCIIString,1}:
>> "x1"
>> "y1"
>> "x2"
>> "y2"
>> "x3"
>> "y3"
>>
>> julia> reshape(d,3,2)
>> 3x2 Array{ASCIIString,2}:
>> "x1" "y2"
>> "y1" "x3"
>> "x2" "y3"
>>
>> you see the problem ? instead I would like to have :
>> x1 y1
>> x2 y2
>> ..
>> xn yn
>>
>> because I want to be able to work on columns and line ... of course
>> another easy solution is to use dataframes, but I tried with arrays because
>> the code should be faster... :)
>>
>> Le mardi 12 avril 2016 16:27:50 UTC+2, Tim Holy a écrit :
>>>
>>> Note that in `a = Array{Float64,2}`, `a` is a *type*, not an *instance*.
>>> You
>>> presumably mean `a = Array(Float64, 0, 0)`.
>>>
>>> But Yichao is right that you can't grow a 2d array, only a 1d one.
>>>
>>> Best,
>>> --Tim
>>>
>>
