Hi all, I noticed the following (unexpected for me) behaviour:
a = NA.arange(12) a.shape = (3,4) a[[0,2]][:,:2] = a[[0,2]][:,2:] print a array([[ 0, 1, 2, 3], [ 4, 5, 6, 7], [ 8, 9, 10, 11]])
rather than array([[ 2, 3, 2, 3], [ 4, 5, 6, 7], [ 10, 11, 10, 11]]) as I was expecting. This happens only if I try to combine indices lists with slices. Is it by design or I ran into a bug? curzio
On Jul 11, 2005, at 1:38 PM, Curzio Basso wrote:
Hi all,
I noticed the following (unexpected for me) behaviour:
a = NA.arange(12) a.shape = (3,4) a[[0,2]][:,:2] = a[[0,2]][:,2:] print a array([[ 0, 1, 2, 3], [ 4, 5, 6, 7], [ 8, 9, 10, 11]])
rather than
array([[ 2, 3, 2, 3], [ 4, 5, 6, 7], [ 10, 11, 10, 11]])
as I was expecting. This happens only if I try to combine indices lists with slices. Is it by design or I ran into a bug?
curzio
An array used as an index produces a new copy (if you think about it, given the possibilities, there isn't much else that can be done). So the entity on the left of your expression is modified, but since nothing refers to it, it is discarded immediately thereafter. The array 'a' itself was never changed. I'd say that it isn't either a bug or feature. Perry Greenfield
participants (2)
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Curzio Basso -
Perry Greenfield