[Numpy-discussion] object arrays and ==

[Ryan May]

On Mon, May 4, 2009 at 3:55 PM, David Warde-Farley <dwf at cs.toronto.edu>wrote:

> Hi,
>
> Is there a simple way to compare each element of an object array to a
> single object? objarray == None, for example, gives me a single
> "False". I couldn't find any reference to it in the documentation, but
> I'll admit, I wasn't quite sure where to look.
>

I think it might depend on some factors:

In [1]: a = np.array(['a','b'], dtype=np.object)

In [2]: a=='a'
Out[2]: array([ True, False], dtype=bool)

In [3]: a==None
Out[3]: False

In [4]: a == []
Out[4]: False

In [5]: a == ''
Out[5]: array([False, False], dtype=bool)

In [6]: a == dict()
Out[6]: array([False, False], dtype=bool)

In [7]: numpy.__version__
Out[7]: '1.4.0.dev6885'

In [8]: a == 5
Out[8]: array([False, False], dtype=bool)

In [9]: a == 5.
Out[9]: array([False, False], dtype=bool)

But based on these results, I have no idea what the factors might be.  I
know this works with datetime objects, but I'm really not sure why None and
the empty list don't work.

Ryan

-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma
Sent from Norman, Oklahoma, United States
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