On 29/04/2008, Keith Goodman
On Tue, Apr 29, 2008 at 11:21 AM, Alan G Isaac
wrote: On Tue, 29 Apr 2008, Keith Goodman apparently wrote:
I often use x[i,:] and x[:,i] where x is a matrix and i is a scalar. I hope this continues to return a matrix.
1. Could you give an example of the circumstances of this use?
In my use i is most commonly an array (i = M.where(y.A)[0] where y is a nx1 matrix), sometimes a list, and in ipython when debugging or first writing the code, a scalar. It would seem odd to me if x[i,:] returned different types of objects based on the type of i:
array index idx = M.where(y.A)[0] where y is a nx1 matrix x[dx,:] --> matrix
list index idx = [0] x[idx,:] --> matrix?
scalar index idx = 0 x[idx,:] --> not matrix
It is actually pretty unreasonable to hope that A[0] and A[[1,2,3]] or A[[True,False,True]] should return objects of the same rank. Anne