On Tue, Apr 16, 2013 at 7:45 PM, Ondřej Čertík <ondrej.cer...@gmail.com>wrote:
> On Tue, Apr 16, 2013 at 4:55 PM, Bob Nnamtrop <bob.nnamt...@gmail.com> > wrote: > > I am curious if others have noticed an issue with datetime64 at the > > beginning of 1970. First: > > > > In [144]: (np.datetime64('1970-01-01') - np.datetime64('1969-12-31')) > > Out[144]: numpy.timedelta64(1,'D') > > > > OK this look fine, they are one day apart. But look at this: > > > > In [145]: (np.datetime64('1970-01-01 00') - np.datetime64('1969-12-31 > 00')) > > Out[145]: numpy.timedelta64(31,'h') > > > > Hmmm, seems like there are 7 extra hours? Am I missing something? I don't > > see this at any other year. This discontinuity makes it hard to use the > > datetime64 object without special adjustment in ones code. I assume this > a > > bug? > > Indeed, this looks like a bug, I can reproduce it on linux as well: > > In [1]: import numpy as np > > In [2]: np.datetime64('1970-01-01') - np.datetime64('1969-12-31') > Out[2]: numpy.timedelta64(1,'D') > > In [3]: np.datetime64('1970-01-01 00') - np.datetime64('1969-12-31 00') > Out[3]: numpy.timedelta64(31,'h') > > Maybe, maybe not... were you alive then? For all we know, Charles and co. were partying an extra 7 hours every day back then? Just sayin' Ben Root
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