How can I convert 2D array of objects to 2D double array?

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Hi,
How can I convert 2D array of C# objects(saMatrix) to 2D double array (dArray)?

Thanks.

Int32 iDim = 3;
object saMatrix = null;

- saMatrix {object[3, 3]} object {object[,]}
[0, 0] 11.0 object {double}
[0, 1] 12.0 object {double}
[0, 2] 13.0 object {double}
[1, 0] 21.0 object {double}
[1, 1] 22.0 object {double}
[1, 2] 23.0 object {double}
[2, 0] 31.0 object {double}
[2, 1] 32.0 object {double}
[2, 2] 33.0 object {double}
//TO
double[,] dArray = new double[iDim, iDim];

Posted 13-Apr-15 11:58am

oleg63

Updated 1-Jun-18 10:47am

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Sergey Alexandrovich Kryukov 13-Apr-15 18:32pm

The question makes no sense. It all depends on how you want to map those matrices and their elements.
—SA

oleg63 14-Apr-15 10:10am

Yes, it does.
It's square matrix. Essentially it passed back to the C# client from COM interface as safearray of variants(which are double type).
On C# side, I see it as described above.
It's need to be converted in 2D matrix of double.
So, if you know the answer, please submit it below,
if don't, just do not pollute the forum with the useless answers.

Sergey Alexandrovich Kryukov 14-Apr-15 10:18am

If you take the labor of explaining what you want to achieve properly, I'll probably answer.
—SA

oleg63 14-Apr-15 13:35pm

It's fun to see you as "Top Expert in 24hrs".
Looks like answers like this work as well ;)

Sergey Alexandrovich Kryukov 14-Apr-15 15:17pm

Fun? No they don't. You assume too much. You did not really read my posts to judge. Don't try to put responsibilities on your sloppiness to others. Please, nothing personal. If you provide reasonable information, I'll gladly give you very comprehensive answer as I usually do, despite of all your rudeness and lack of collaboration you demonstrate right now.
—SA

Sinisa Hajnal 14-Apr-15 3:25am

Read MSDN on Array and ArrayList objects there are lots of converters, there are some on IEnumerable too, some of them generics where you can specify types. See if any of them help.

Sergey Alexandrovich Kryukov 14-Apr-15 10:17am

ArrayList should not be used.
—SA

oleg63 14-Apr-15 10:36am

Thanks Sinsa,
So far I've found 2 types of conversions, but they both work on 1D array.
Like:
double[] E_x = ((object[])_x).Cast<double>().ToArray();
Array.ConvertAll<object, double>(...)

Sergey Alexandrovich Kryukov 14-Apr-15 15:18pm

Very bad. I tell you, you need to explain how a matrix should be represented. What, an array of double? anything else? And how the objects representing matrix should be arranged. That's all, simple enough.
—SA

oleg63 14-Apr-15 15:39pm

SA, sorry if I in some way hurt you. But it's very basic straightforward conversion of square matrix NxN type of object, to the absolutely same dimensioning (2D array), but type of double.
I've found how to do that for 1D arrays, but I need conversion for 2D arrays.
Thanks for the answer.

Sergey Alexandrovich Kryukov 14-Apr-15 15:49pm

No hurting, please forget it. Let's start over: what are the elements of the matrix, are they already of double type? If not, what is the element type? If the matrix is not implemented as "simply array", it should have some kind of interface where you get an element by X-Y index (row-column index). What is the return type representing the type of element?

Now, if you have only one matrix NxN, the solution would be an array NxN. What do you expect if you have M different matrices? Say, it could be the array N*M x N, or array N x N*M, or something else? I think my questions are natural and should be understandable.

Now, What have you tried so far? If this is what I assumed above, or something just a bit different, it looks like a very simple problem: allocate the array of required size, and then populate if in some loops. What's the problem?

And, finally, why doing all that, what's the goal?

—SA

oleg63 14-Apr-15 16:45pm

So, let's start...
There is a COM server, which has a routine:
[id(332), helpstring("method GetAMatrix")] HRESULT GetAMatrix([in] LONG iDimensions,[out] VARIANT *saMatrix,[in,out] SHORT* iErr);

iDimensions - dimensions of square matrix(for 3 dim, it would be matrix 3X3 ;)
saMatrix - the square matrix of beforemensioned size, which is formed by COM server as 2D SAFEARRAY of VARIANTs(internally each VARIANT variable is type of double, vt = double).
On C# side we have:
private void button_test_Click(object sender, EventArgs e)
{
Int32 iDim = 3;
object saMatrix = null;
theCOM.GetAMatrix(iDim, out saMatrix, ref iErr);
double[,] dArray = new double[iDim, iDim];
//put your conversion from saMatrix to dArray HERE ;)
...
}

C# object browser has the COM routine description:
GetAMatrix( int, out object, ref short)

Returned matrix look(from the C# debugger):
- saMatrix {object[3, 3]} object {object[,]}
[0, 0] 11.0 object {double}
[0, 1] 12.0 object {double}
[0, 2] 13.0 object {double}
[1, 0] 21.0 object {double}
[1, 1] 22.0 object {double}
[1, 2] 23.0 object {double}
[2, 0] 31.0 object {double}
[2, 1] 32.0 object {double}
[2, 2] 33.0 object {double}

I guess it's detailed enough(if you know the COM :)

The casting technique, which I've described earlier work only on one-dimensional arrays, and do not work for 2D arrays, which is my matrix. This is a problem. Oh, a Goal... ;-\ - pass the matrix(basically 2D array of double type) from COM server to the C# client...

So what do think about it???

Sergey Alexandrovich Kryukov 14-Apr-15 16:50pm

I think that you simply need to do it all element by element. Really. Create an array of expected size and populate it.
Hard to say how did you end up with such trash (VARIANT was a really bad idea of COM even in first place) you have to use, could be some legacy...
—SA

oleg63 14-Apr-15 16:57pm

You will end up with such trash, if your COM server would require support any kind of clients(early binding, and late binding), and only automation types will do the job.

Sergey Alexandrovich Kryukov 14-Apr-15 17:03pm

I see...
—SA

Sinisa Hajnal 14-Apr-15 15:32pm

Yeah, sorry about that, I've read too fast and read that you need to convert matrix into arrays, not one array.

Trivial way is to use 1D tranformation on rows and assign each resulting array to your matrix - or even to loop through each element on both axes.

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Wendell D H · Accepted Answer · 2015-04-17T05:35:00

I looked for ways to do it with Array.ConvertAll, but was having trouble.
But this should work.
This assumes you don't know the sizes of the array dimentions

C#

//Your original object
object saMatrix = new object[3, 3] {{ 11.0, 12.0, 13.0 },
                                    { 21.0, 22.0, 23.0 },
                                    { 31.0, 32.0, 33.0 } };

//Create an array of doubles the same size.
double[,] dArray = new double[((object[,])saMatrix).GetUpperBound(0) + 1,
                              ((object[,])saMatrix).GetUpperBound(1) + 1];

//Cast and fill each item
for (int x = 0; x <= ((object[,])saMatrix).GetUpperBound(0); x++)
{
   for (int y = 0; y <= ((object[,])saMatrix).GetUpperBound(1); y++)
   {
     dArray[x, y] = (double)((object[,])saMatrix)[x, y];
   }
}

How can I convert 2D array of objects to 2D double array?

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How can I convert 2D array of objects to 2D double array?

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