[Numpy-discussion] Missing/accumulating data

[Christopher Barker]

Mark Wiebe wrote:
>     Speaking of which, would we make the NA value be false?
> 
> For booleans, it works out like this:
> 
> http://en.wikipedia.org/wiki/Ternary_logic#Kleene_logic

That's pretty cool!

> In R, trying to test the truth value of NA ("if (NA) ...") raises an 
> exception. Adopting this behavior seems reasonable to me.

I'm not so sure. the other president is Python, where None is 
interpreted as False.

In general, in non-numpy code, I use None to mean "not set yet" or "I'm 
not sure", or, whatever. It's pretty useful to have it be false.

However, I also do:

if x is not None:

rather than-

if x:

so as to be unambiguous about what I'm testing for (and because if x == 
0, I don't want the test to fail), so I guess:

if arr[i] is np.NA:

would be perfectly analogous.

-Chris






> -Mark
>  
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>     -Chris
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-- 
Christopher Barker, Ph.D.
Oceanographer

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