calendar-count-between {clock}

Counting: calendars

Description

calendar_count_between() counts the number of precision units between start and end (i.e., the number of years or months). This count corresponds to the whole number of units, and will never return a fractional value.

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:

• year-month-day

• year-month-weekday

• year-week-day

• iso-year-week-day

• year-quarter-day

• year-day

Usage

calendar_count_between(start, end, precision, ..., n = 1L)

Arguments

start, end

⁠[clock_calendar]⁠

A pair of calendar vectors. These will be recycled to their common size.

precision

⁠[character(1)]⁠

A precision. Allowed precisions are dependent on the calendar used.

...

These dots are for future extensions and must be empty.

n

⁠[positive integer(1)]⁠

A single positive integer specifying a multiple of precision to use.

Value

An integer representing the number of precision units between start and end.

Comparison Direction

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 start and end will never change after adding the count to start. This makes this function useful for repeated count computations at increasingly fine precisions.

Examples

# Number of whole years between these dates
x <- year_month_day(2000, 01, 05)
y <- year_month_day(2005, 01, 04:06)

# Note that `2000-01-05 -> 2005-01-04` is only 4 full years
calendar_count_between(x, y, "year")