[SciPy-User] numpy.where() issue

[Sebastian]

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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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