Numeric slicing, iteration prob.
fperez528 at yahoo.com
Mon Aug 5 18:20:01 EDT 2002
Duncan Smith wrote:
> Does anyone know of a cuter way of iterating over an index rather
> than building strings and using eval()? (Example below.) This will get more
> awkward when I need to do further slicing. eg. depending on the results
> returned I might need to generate t[1,:,3], t[:,1,3] etc.
Can't think of a nicer one right now, but there probably is one. Maybe build
the necessary index structures and use take()? Don't know...
> On a related note, does anyone have a feeling for the most efficient way of
> checking if all the values in a returned slice are zero? I can obviously
> just iterate over the cells and break when I get a non-zero value, but I'm
> hoping there's some more efficient method available in Numeric. TIA.
Look into alltrue:
In : import Numeric as N
In : N.alltrue ?
Base Class: <type 'function'>
String Form: <function alltrue at 0x82e31f4>
Namespace: Currently not defined in user session.
Definition: N.alltrue(x, axis=0)
Perform a logical_and over the given axis.
That may help.
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