Re: [Numpy-discussion] FutureWarning: comparison to `None` will result in an elementwise object comparison in the future.

On 08.04.2015 20:30, Nathaniel Smith wrote:

On Apr 8, 2015 2:16 PM, "Andreas Hilboll" mailto:lists@hilboll.de> wrote:

...

Hi all,

I'm commonly using function signatures like

def myfunc(a, b, c=None): if c is None: # do something ... ...

where c is an optional array argument. For some time now, I'm getting a

FutureWarning: comparison to `None` will result in an elementwise object comparison in the future

from the "c is None" comparison. I'm wondering what would be the best way to do this check in a future-proof way?

As far as I know, you should be getting the warning when you write c == None and the fix should be to write c is None instead. (And this is definitely an important fix -- it's basically a bug in numpy that the == form ever worked.) Are you certain that you're getting warnings from 'c is None'?

My mistake; I was actually doing if p1 is None == h1 is None: instead of if (p1 is None) == (h1 is None): Sorry for the noise. -- Andreas.