[Numpy-discussion] bad generator behaviour with sum

Charles R Harris charlesr.harris at gmail.com
Sun Aug 27 14:58:35 CDT 2006


Hi,

The problem seems to arise in the array constructor, which treats the
generator as a python object and creates an array containing that object.
So, do we want the possibility of an array of generators or should we
interpret it as a sort of list? I vote for that latter.

Chuck

On 8/27/06, Charles R Harris <charlesr.harris at gmail.com> wrote:
>
> Hi Christopher,
>
> On 8/27/06, Charles R Harris <charlesr.harris at gmail.com> wrote:
> >
> > Hi,
> >
> > On 8/27/06, listservs at mac.com <listservs at mac.com> wrote:
> > >
> > > -----BEGIN PGP SIGNED MESSAGE-----
> > > Hash: SHA1
> > >
> > > It seems like numpy.sum breaks generator expressions:
> > >
> > > In [1]: sum(i*i for i in range(10))
> > > Out[1]: 285
> > >
> > > In [2]: from numpy import sum
> > >
> > > In [3]: sum(i*i for i in range(10))
> > > Out[3]: <generator object at 0x10eca58>
> > >
> > > Is this intentional? If so, how do I get the behaviour that I am
> > > after?
> > >
> >
> >
> > In [3]: sum([i*i for i in range(10)])
> > Out[3]: 285
> >
> > Chuck
> >
>
> The numarray.sum also fails to accept a generator as an argument. Because
> python does and the imported sum overwrites it, we should probably check the
> argument type and make it do the right thing.
>
> Chuck
>
>
>
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