[Numpy-discussion] What is the logical value of nan?

Sturla Molden sturla@molden...
Wed Mar 11 07:12:04 CDT 2009

Charles R Harris wrote:
> It isn't 0 so it should be True. Any disagreement?... Chuck
NaN is not a number equal to 0, so it should be True?

NaN is not a number different from 0, so it should be False?

Also see Pearu's comment.

Why not raise an exception when NaN is evaluated in a boolean context? 
bool(NaN) has no obvious interpretation, so it should be considered an 

Sturla Molden

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