calendar_count_between() counts the number of
precision units between
end (i.e., the number of years or months). This count
corresponds to the whole number of units, and will never return a
This is suitable for, say, computing the whole number of years or months between two calendar dates, accounting for the day and time of day.
Each calendar has its own help page describing the precisions that you can count at:
- start, end
A pair of calendar vectors. These will be recycled to their common size.
A precision. Allowed precisions are dependent on the calendar used.
These dots are for future extensions and must be empty.
A single positive integer specifying a multiple of
The computed count has the property that if
start <= end, then
start + <count> <= end. Similarly, if
start >= end, then
start + <count> >= end. In other words, the comparison direction between
end will never change after adding the count to
makes this function useful for repeated count computations at
increasingly fine precisions.