W = week (T) returns the week-of-year number for each element of the input datetime array T. The output W is a double array containing integer values in the range $[1,\; 54]$ and it has the same size as T. Weeks are counted from Sunday to Saturday, and the week containing January 1 is week 1. Not-A-Time (NaT) values in T are returned as NaN in the output array.

W = week (T, weekType) returns the week number for each element of the input datetime array T as specified by weekType, which may have any of the following options:

• 'weekofyear' (default) returns the week of the year in a numeric array, in the range $[1,\; 54]$.
• 'weekofmonth' returns the week of the month in a numeric array, in the range $[1,\; 6]$.

Source Code: datetime