On Fri, Jun 19, 2015 at 4:15 PM, Chris Barker <chris.barker@noaa.gov> wrote:

On Wed, Jun 17, 2015 at 11:13 PM, Nathaniel Smith <njs@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.Barker@noaa.gov

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