Returns, for a given absolute time, the ordinal number of a smaller calendar unit (such as a day) within a specified larger calendar unit (such as a week).
- iOS 2.0+
- macOS 10.4+
- tvOS 9.0+
- watchOS 2.0+
The smaller calendar unit
The larger calendar unit
The absolute time for which the calculation is performed
The ordinal number of
larger at the time specified by
larger is not logically bigger than
smaller in the calendar, or the given combination of units does not make sense (or is a computation which is undefined).
The ordinality is in most cases not the same as the decomposed value of the unit. Typically return values are
1 and greater. For example, the time
00: is in the first hour of the day, and for units Hour and Day respectively, the result would be
1. An exception is the week-in-month calculation, which returns
0 for days before the first week in the month containing the date.
Note that some computations can take a relatively long time.