Test whether time is determinate at a granule's precision

time_is_determinate_at() tests, for each element of a mixtime vector, whether the time point is well-defined at the precision of granule.

Usage

time_is_determinate_at(x, granule, ...)

Arguments

x

A time object (typically a mixtime vector).

granule

The time granule whose precision to test, given as a granule generator (e.g. cal_gregorian$month) or a sized time unit (e.g. cal_gregorian$month(1L)).

...

Additional arguments for methods.

Value

A logical vector the same length as x.

Details

Discrete (integer) time cannot resolve a granule finer than its own chronon (a year() has no determinate month), so those elements are FALSE. Continuous (fractional) time tracks progress within its chronon and so resolves finer granules exactly (0% through 2020 is 0% through January), giving TRUE. Coarser-or-equal granules are always determinate. Missing (NA) and infinite times give NA.

Examples

# Discrete: a year has no determinate month
time_is_determinate_at(year(2020L), cal_gregorian$month(1L))
#> [1] FALSE

# Continuous: 0% through 2020 is 0% through January
time_is_determinate_at(year(2020), cal_gregorian$month(1L))
#> [1] TRUE

# A coarser granule is always determinate
time_is_determinate_at(yearmonth(as.Date("2020-02-01")), cal_gregorian$year(1L))
#> [1] TRUE