ordinality(of:in:for:)
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).
Declaration
func ordinality(of smaller: NSCalendar.Unit, in larger: NSCalendar.Unit, for date: Date) -> IntParameters
- smaller:
The smaller calendar unit
- larger:
The larger calendar unit
- date:
The absolute time for which the calculation is performed
Return Value
The ordinal number of smaller within larger at the time specified by date. Returns NSNotFound if 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).
Discussion
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 00:45 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.