The DayOfYear( d ) command computes the day of the year of the Date object d.

The DayOfYear( year, month, day ) command computes the day of the year for the day-th day of the month month (1..12) in the year year.

The day of the year of January 1 is equal to 1.  The last day of the year (December 31) is usually either $365$, for an ordinary year, or $366$ for a leap year.

$\mathrm{with}\left(\mathrm{Calendar}\right)\:$

$\mathrm{DayOfYear}\left(\mathrm{Date}\left(\right)\right)$

$68$

$\mathrm{DayOfYear}\left(2000\,1\,1\right)$

$1$

$\mathrm{DayOfYear}\left(2000\,12\,31\right)$

$366$

$\mathrm{DayOfYear}\left(2100\,12\,31\right)$

$365$

$\mathrm{DayOfYear}\left(1900\,12\,31\right)$

$365$

$\mathrm{DayOfYear}\left(\mathrm{Date}\left(1900\,12\,31\right)\right)$

$365$

$\mathrm{DayOfYear}\left(1582\,12\,31\right)$

$355$

$\mathrm{DayOfYear}\left(1066\,10\,14\right)$

$287$

$\mathrm{DayOfYear}\left(1066\,12\,25\right)$

$359$

The Calendar[DayOfYear] command was introduced in Maple 2018.

For more information on Maple 2018 changes, see Updates in Maple 2018.