[Numpy-discussion] Syntax equivalent for np.array()

Gökhan Sever gokhansever at gmail.com
Wed Feb 10 11:12:49 EST 2010


On Wed, Feb 10, 2010 at 10:06 AM, Angus McMorland <amcmorl at gmail.com> wrote:

> On 10 February 2010 11:02, Gökhan Sever <gokhansever at gmail.com> wrote:
> > Hi,
> >
> > Simple question:
> >
> > I[4]: a = np.arange(10)
> >
> > I[5]: b = np.array(5)
> >
> > I[8]: a*b.cumsum()
> > O[8]: array([ 0,  5, 10, 15, 20, 25, 30, 35, 40, 45])
> >
> > I[9]: np.array(a*b).cumsum()
> > O[9]: array([  0,   5,  15,  30,  50,  75, 105, 140, 180, 225])
> >
> > Is there a syntactic equivalent for the I[9] --for instance instead of
> using
> > "list" keyword I use [ ] while creating a list. Is there a shortcut for
> > np.array instead of writing np.array(a*b) explicitly?
>
> How about just (a*b).cumsum() ?
>
> Angus.
> --
> AJC McMorland
> Post-doctoral research fellow
> Neurobiology, University of Pittsburgh
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>

Yep that's it :) I knew that it was a very simple question.

What confused me is I remember somewhere not sure maybe in IPython dev I
have gotten when I do:

(a*b).cumsum()

AttributeError: 'tuple' object has no attribute 'cumsum' error.

So I was thinking ( ) is a ssugar for tuple and np.array might have
something special than these.

-- 
Gökhan
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