On Fri, Jun 19, 2015 at 4:15 PM, Chris Barker <chris.bar...@noaa.gov> wrote:
> On Wed, Jun 17, 2015 at 11:13 PM, Nathaniel Smith <n...@pobox.com> wrote: > >> there's some >> argument that in Python, doing explicit type checks like this is >> usually a sign that one is doing something awkward, > > > I tend to agree with that. > > On the other hand, numpy itself is kind-of sort-of statically typed. But > in that case, if you need to know the type of an array -- check the array's > dtype. > > Also: > > >>> a = np.zeros(7, int) > >>> n = a[3] > >>> type(n) > <type 'numpy.int64'> > > I Never liked declaring numpy arrays with the python types like "int" or > "float" -- in numpy you usually care more about the type, so should simple > use "int64" if you want a 64 bit int. And "float64" if you want a 64 bit > float. Granted, pyton floats have always been float64 (on all platfroms??), > and python ints used to a be a reasonable int type, but now that python > ints are bigInts in py3, it really makes sense to be clear. > > And now that I think about it, in py2, int is 32 bit on win64 and 64 bit > on *nix64 -- so you're really better off being explicit with your numpy > arrays. > being late checking some examples >>> a = np.zeros(7, int) >>> a.dtype dtype('int32') >>> np.__version__ '1.9.2rc1' >>> type(a[3]) <class 'numpy.int32'> >>> a = np.zeros(7, int) >>> a = np.array([888888888888888888]) >>> a array([888888888888888888], dtype=int64) >>> a = np.array([888888888888888888888888888888888]) >>> a array([888888888888888888888888888888888], dtype=object) >>> a = np.array([888888888888888888888888888888888], dtype=int) Traceback (most recent call last): File "<pyshell#10>", line 1, in <module> a = np.array([888888888888888888888888888888888], dtype=int) OverflowError: Python int too large to convert to C long Looks like we need to be a bit more careful now. Josef Python 3.4.3 > > -CHB > > > -- > > Christopher Barker, Ph.D. > Oceanographer > > Emergency Response Division > NOAA/NOS/OR&R (206) 526-6959 voice > 7600 Sand Point Way NE (206) 526-6329 fax > Seattle, WA 98115 (206) 526-6317 main reception > > chris.bar...@noaa.gov > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > >
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