On Nov 13, 2007 6:57 AM, Sebastian Haase <[EMAIL PROTECTED]> wrote: > On Nov 13, 2007 2:18 PM, Stefan van der Walt <[EMAIL PROTECTED]> wrote: > > Hi Sebastian > > > > On Tue, Nov 13, 2007 at 01:11:33PM +0100, Sebastian Haase wrote: > > > Hi, > > > I need to check the array dtype in a way that it is ignoring > > > differences coming only from big-endian vs. little-endian. > > > > Does > > > > N.issubdtype(first_dtype, second_dtype) > > > > work? > > Hi Stéfan ! > It appears to work : > > >>> N.empty(5, dtype=">f").dtype==N.float32 > False > >>> N.empty(5, dtype="<f").dtype==N.float32 > True > >>> a = N.empty(5, dtype=">f") > >>> a.dtype > >f4 > >>> a.dtype.type > <type 'numpy.float32'> > >>> N.issubdtype(a.dtype, N.float32) > True > >>> a = N.empty(5, dtype=">?") > >>> a.dtype > bool > >>> a = N.empty(5, dtype="<?") > >>> a.dtype > bool > >>> a = N.empty(5, dtype=">?") > >>> N.issubdtype(a.dtype, N.bool) > True > >>> N.issubdtype(a.dtype, N.bool_) > True > > Furthermore however, > >>> N.empty(5, dtype=">?").dtype == N.empty(5, dtype="<?").dtype > True > > So, for "symmetry reasons" with my existing non-bool code, I would > likely use "arr.dtype.type == N.bool_". > Still wondering what the "_" means here. (reading the book did not > enlighten....)
Out of curiosity, does it work with arr.dtype.type == N.float? I would expect not, and I imagine that is the same reason that it doesn't work for N.bool. Which is that N.bool is __builtin__.bool or, in other words, N.boolis just Python's boolean type. I believe this is to protect those foolish enough to use "from x import *". Anyway, N.bool_ is the real, numpy boolean dtype that is analogous to unit8 and friends. > > > Thanks, > Sebastian > _______________________________________________ > Numpy-discussion mailing list > [email protected] > http://projects.scipy.org/mailman/listinfo/numpy-discussion > -- . __ . |-\ . . [EMAIL PROTECTED]
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