[SciPy-dev] Arrays as truth values?

Travis Oliphant oliphant at ee.byu.edu
Thu Nov 10 14:35:17 CST 2005


>I'm not quite sure how any() is supposed to work; does it just return
>true if one or more element evaluates to true?
>
>  
>
Yes.  Exactly.  There is an axis argument, but for just testing truth of 
anything in the array you don't want to use it.

>In my current code, I have the following:
>
>if sum(lower>=median or median>=upper): <do something>
>
>which returns a ValueError. What is the best way to detect elements in
>one array that are less than the corresponding element in the other
>without constructing a list comprehension?
>  
>
The ValueError was just recently added because it is ambiguous as to 
what you meant by this.

I would say

if any(lower>=media) or any(median>=upper):  <do something>


-Travis




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