On 2014/09/21, 11:10 AM, Demitri Muna wrote:
Hi,
I just encountered the following in my code:
FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.
I'm very concerned about this. This is a very common programming pattern (lazy loading):
class A(object): def __init__(self): self._some_array = None
@property def some_array(self): if self._some_array == None: # perform some expensive setup of array return self._some_arrayIt seems to me that the new behavior will break this pattern. I think that redefining the "==" operator is a little too aggressive here. It strikes me as very nonstandard and not at all obvious to someone reading the code that the comparison is a very special case for numpy objects. Unless there's some aspect I'm missing here, I think an element-wise comparator should be more explicit.
I think what you are missing is that the standard Python idiom for this use case is "if self._some_array is None:". This will continue to work, regardless of whether the object being checked is an ndarray or any other Python object.
Eric
Cheers, Demitri
Demitri Muna
Department of Astronomy Le Ohio State University
http://trillianverse.org http://scicoder.org
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