[Numpy-discussion] matrix indexing question
Alan G Isaac
aisaac@american....
Sun Mar 25 13:39:03 CDT 2007
> Em Dom, 2007-03-25 às 13:07 -0400, Alan G Isaac escreveu:
>> >>> x[1]
>> matrix([[1, 0]])
>> feels wrong. (Similarly when iterating across rows.)
On Sun, 25 Mar 2007, Paulo Jose da Silva e Silva apparently wrote:
> I think the point here is that if you are using matrices,
> then all you "should" want are matrices, just like in
> MATLAB:
> >> b = A(1, :)
> b =
> 1 2
Yes, that is the idea behind this, which I am also
accustomed to from GAUSS. But note again that the Matlab
equivalent ::
>>> x=N.mat('1 2;3 4')
>>> x[0,:]
matrix([[1, 2]])
does provide this behavior. The question I am raising
is a design question and is I think really not addressed
by the rule of thumb you offer. Specifically, that rule
of thumb if it is indeed the justification of ::
>>> x[1]
matrix([[3, 4]])
finds itself in basic conflict with the idea that I ought to
be able to iterate over the objects in an iterable container.
I mean really, does this not "feel" wrong? ::
>>> for item in x: print item.__repr__()
...
matrix([[1, 2]])
matrix([[3, 4]])
Cheers,
Alan Isaac
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