[SciPy-dev] array logical ops error?

Travis Oliphant oliphant at ee.byu.edu
Mon Oct 31 11:26:26 CST 2005


Alan G Isaac wrote:

>On Mon, 31 Oct 2005, Robert Cimrman apparently wrote: 
>  
>
>>is this the expected behaviour? 
>>IMHO (b * c) == (b and c), (b + c) == (b or c) should hold... 
>>    
>>
>
>I expected the Boolean operations to yield  
>element-by-element comparisons.  What are they??  In 
>contrast, the + and * operators give the expected results.
>
>  
>
This is a Python deal.  It would be nice if b and c did the same thing 
as b * c, but Python does not allow overloading of the "and" and "or" 
operators (A PEP to say it should would be possible). 

Thus, "b and c" evaluates the truth of b and the truth of c as a whole 
(not elementwise), and there is no way to over-ride this.

-Travis




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