[Numpy-discussion] truth value of dtypes

Robert Kern robert.kern@gmail....
Fri Dec 10 08:33:40 CST 2010


On Fri, Dec 10, 2010 at 03:13, Nils Becker <n.becker@amolf.nl> wrote:
> Hi,
>
> why is
>
>>>> bool(np.dtype(np.float))
> False
>
> ?
>
> I came across this when using this python idiom:
>
> def f(dtype=None):
> ....if not dtype:
> ........print 'using default dtype'

The default truth value probably should be True, but not for this
reason. The correct idiom to use is this:

def f(dtype=None):
    if dtype is None:
        print 'using default dtype'

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
  -- Umberto Eco


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