[Numpy-discussion] matrix wart

Konrad Hinsen konrad.hinsen@laposte....
Fri Feb 22 09:14:48 CST 2008


On Feb 22, 2008, at 15:55, Travis E. Oliphant wrote:

>> ColumnVector, and RowVector. It would work like this:
>>
>> m = Matrix([[1, 2], [3, 4]])
>>
>> m[0, :] -->  ColumnVector([1, 3])
>> m[:, 0] --> RowVector([1, 2])
>>
> These seem backward to me.    I would think that m[0,:] would be the
> RowVector([1,2]) and m[:,0] be the ColumnVector([1,3]).

Right.

> What is m[0] in this case?  The same as m[0, :]?

Yes.

>> However, the matrix implementation in Numeric was inspired by Matlab,
>> where everything is a matrix. But as I said before, Python is not
>> Matlab.
> It should be kept in mind, however, that Matlab's matrix object is  
> used
> successfully by a lot of people and should not be dismissed as  
> irrelevant.

Matlab's approach is fine for Matlab, of course. All I am saying is  
that it is a misfit for Python. Just like 1-based indexing is used  
successfully by lots of Fortran programmers, but would be an eternal  
source of confusion if it were introduced for a specific container  
object in Python.

Konrad.





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