[Numpy-discussion] truth value of dtypes

Robert Kern robert.kern at gmail.com
Fri Dec 10 09:33:40 EST 2010

On Fri, Dec 10, 2010 at 03:13, Nils Becker <n.becker at 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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