[Numpy-discussion] untenable matrix behavior in SVN

Christopher Barker Chris.Barker@noaa....
Mon Apr 28 14:37:17 CDT 2008

oops, typo!

Christopher Barker wrote:
> Gael Varoquaux wrote:
>> I don't know why people are indexing matrices with A[x][y], but they
>> shouldn't.
> I think there has been a misunderstanding here. I don't think anyone is 
> suggesting that if a coder wants an element of a matrix, that s/he 
> should write that:
> element = M[i,j]

I meant -- no one is suggesting:

element = M[i][j]

because, of course, M[i,j] is exactly what you should do do get an element.

Which, by the way, brings up another inconsistency in the current behavior:

 >>> M
matrix([[1, 2, 3],
         [4, 5, 6],
         [7, 8, 9]])
 >>> M[1,1]
 >>> M[1,:]
matrix([[4, 5, 6]])

so if you pull out a single element, you get a scalar(0-d), but if you 
pull out a row, you get a matrix(2-d). It makes me want vectors more...


Christopher Barker, Ph.D.

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