[SciPy-User] numpy.where() issue

[Oleksandr Huziy]

Maybe this way would be clearer (remember parentheses in the condition are
crucial):

"""
indices = np.where((Yy > 0.02) | (Yy < -0.02))
"""

Cheers


2015-07-15 14:22 GMT-04:00 Sebastian <sebix at sebix.at>:

>
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> Hi,
>
> What is this doing? np.where(Yy > 0.02 or Yy < -0.02)
> Let's split it up
> (Yy > 0.02) or (Yy < -0.02)
> The both < > comparisons give boolean numpy arrays, say a and b.
> a or b
> The python or-Operator works on boolean values, so it does
> bool(a) or bool(b)
> What is "The truth value of an array with more than one element"? It "is
> ambiguous".
> Voila
>
> You can also use
> np.logical_or(np.where(...), np.where(...))
> or shorter
> np.where(...) | np.where(...)
>
> Sebastian
>
> On 07/15/2015 08:13 PM, Gabriele Brambilla wrote:
> > I have problems with numpy.where
> >
> > why if I write
> > deathnote0 = np.where(Yy > 0.02 or Yy < -0.02)
> > I get:
> >
> > Traceback (most recent call last):
> >
> >   File "readingK.py", line 63, in <module>
> >
> >     deathnote0 = np.where(Yy > 0.02 or Yy < -0.02)
> >
> > ValueError: The truth value of an array with more than one element is
> ambiguous. Use a.any() or a.all()
> >
> > while if I do
> >
> > deathnote0 = np.where(Yy > 0.02)
> >
> > deathnote1 = np.where(Yy < -0.02)
> >
> > deathnote = deathnote0 + deathnote1
> >
> > it works?
> >
> >
> > thanks
> >
> >
> > Gabriele
> >
> >
> >
> >
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-- 
Sasha
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