[Numpy-discussion] converting scalar to array with dimension 1

P GM pgmdevlist@gmail....
Fri Mar 30 14:50:38 CDT 2007


Actually, there's even faster than that:

a = 3
a = array(a, ndmin=1)


atleast_1d is nothing but a wrapper function, that works best when used with
several inputs. When using only one array as inputs, the trick above should
be more appropriate.



On 3/30/07, Bill Baxter <wbaxter@gmail.com> wrote:
>
> atleast_1d will do the trick
>
> In [11]: a = 3
> In [12]: a = atleast_1d(a)
> In [13]: shape(a)
> Out[13]: (1,)
> In [14]: a.shape   # also works ;-)
> Out[14]: (1,)
> In [15]: a[0]
> Out[15]: 3
>
> --bb
>
> On 3/30/07, Mark Bakker <markbak@gmail.com> wrote:
> > Hello list -
> >
> > I have a function that normally accepts an array as input, but sometimes
> a
> > scalar.
> > I figured the easiest way to make sure the input is an array, is to make
> it
> > an array.
> > But if I make a float an array, it has 0 dimension, and I can still not
> do
> > array manipulation on it.
> >
> > >>> a = 3
> > >>> a = array(a)
> > >>> shape(a)
> > ()
> > >>> a[0]
> > Traceback (most recent call last):
> >   File "<pyshell#121>", line 1, in ?
> >     a[0]
> > IndexError: 0-d arrays can't be indexed
> >
> > What would be the best (and easiest, this is for an intro class I am
> > teaching) way
> > to convert a to an array (recall, most of the time a is already an
> array).
> >
> > Thanks for your help, Mark
> >
> >
> >
> > _______________________________________________
> > Numpy-discussion mailing list
> > Numpy-discussion@scipy.org
> > http://projects.scipy.org/mailman/listinfo/numpy-discussion
> >
> >
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