Creating an object from YYYY DOY

[Val Schmidt]

I searched around a bit and haven't been able to find a way to create a
datetime object with the year and day of year, instead of year, month, day
of month.

Is this possible?

If not, does anyone have any suggestions regarding how I might convert from
YYYY-DOY to unix seconds?  I can do it through several calls within
Data:::Manip (ParseData() and UnixDate().) but it's EXTREME:LY slow.

Any help would be fantastic!

Thanks,

Val