# [SciPy-user] execute function on an array elementwise

Pieter pieter.cogghe@gmail....
Thu Apr 10 03:31:48 CDT 2008

```Hi,

Thanks for the answers, I think vectorize was the one I was looking
for. My example function was really bad, I'm sorry for that.

I'm actually reading an image and have to convert every pixel value to
an 8 bit vector.

thanks a lot,

Pieter

2008/4/7, lorenzo bolla <lbolla@gmail.com>:
> or simply:
>
> def myFunction(X):
>     return where(X > 3, "some value", "other value")
>
> hth,
> L.
>
>
> On Mon, Apr 7, 2008 at 3:33 PM, J-Pascal Mercier
> <jean-pascal.mercier@inrialpes.fr> wrote:
>
> > Hi Pieter,
> >
> > You could use something like :
> >
> > def myFunction(X):
> >        res = zeros(X.shape)
> >        res[where(X > 3)] = "some value"
> >        res[where(X <= 3)] = "another value"
> >        return res
> >
> > cheers,
> >
> >
> > J-Pascal
> >
> > Projet PRIMA - Laboratoire LIG
> > INRIA Grenoble Rhone-Alpes Research Centre
> > 655, Avenue de l'Europe
> > 38330 Montbonnot, France
> >
> >
> >
> > On 7-Apr-08, at 3:18 PM, Pieter wrote:
> >
> > > Hi all,
> > >
> > > I guess this is an easy one, but can't seem to find it. Suppose I have
> > > this function:
> > >
> > > def myFunction(x):
> > >  result = None
> > >  if x > 3:
> > >    result = "some value"
> > >  else:
> > >    result = "another value"
> > >  return result
> > >
> > > And I want to run it on an array a:
> > > b = myFunction(a)
> > >
> > > which then returns an array with "some value" and "another value". I
> > > could loop over the array, but I guess there's a better way to do
> > > this? (something like arrayMagic from Matlab if I'm not mistaken.
> > >
> > > thanks a lot,
> > >
> > > Pieter
> > >
> > >
> > >
> > > --
> > > Pieter Cogghe
> > > Ganzendries 186
> > > 9000 Gent
> > > 0487 10 14 21
> > > _______________________________________________
> > > SciPy-user mailing list
> > > SciPy-user@scipy.org
> > > http://projects.scipy.org/mailman/listinfo/scipy-user
> > >
> >
> > _______________________________________________
> > SciPy-user mailing list
> > SciPy-user@scipy.org
> > http://projects.scipy.org/mailman/listinfo/scipy-user
> >
>
>
>
> --
> Lorenzo Bolla
> lbolla@gmail.com
> http://lorenzobolla.emurse.com/
> _______________________________________________
>  SciPy-user mailing list
>  SciPy-user@scipy.org
>  http://projects.scipy.org/mailman/listinfo/scipy-user
>
>

--
Pieter Cogghe
Ganzendries 186
9000 Gent
0487 10 14 21
```