[R] How to convert number (matlab) to date

[Gabor Grothendieck]

2011/7/19 Prof Brian Ripley <ripley at stats.ox.ac.uk>:
>> but even this is dubious, since there is no year 0 AD. In Gregorian
>> and Julian calendars, 1 BC continues directly into 1 AD.
>
> True, but these days we are ruled by ISO 8601:2004, which does define a year
> 0 (the year before 1CE aka 1AD). See
> http://en.wikipedia.org/wiki/0_(year) .
>
> It seems also to redefine the meaning of 'Gregorian calendar' calling what
> you are referring to the 'BC/AD calendar system'.  (Those who prefer BCE/CE
> to BC/AD might note the usage of the latter in the definitive international
> standard.)

The Date class has not been extended to support "0000-00-00"; rather,
the origin
argument of as.Date.numeric has been extended to allow "0000-00-00".  There is
no real difference between something like origin = "0000-00-00" and
origin = "matlab", say.

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