CFfactor_units {CFtime}

Number of base time units in each factor level

Description

Given a factor as returned by CFfactor() and the CFtime instance from which the factor was derived, this function will return a numeric vector with the number of time units in each level of the factor.

Usage

CFfactor_units(cf, f)

Arguments

cf

CFtime. An instance of CFtime.

f

factor or list. A factor or a list of factors derived from the parameter cf. The factor or list thereof should generally be generated by the function CFfactor().

Details

The result of this function is useful to convert between absolute and relative values. Climate change anomalies, for instance, are usually computed by differencing average values between a future period and a baseline period. Going from average values back to absolute values for an aggregate period (which is typical for temperature and precipitation, among other variables) is easily done with the result of this function, without having to consider the specifics of the calendar of the data set.

If the factor f is for an epoch (e.g. spanning multiple years and the levels do not indicate the specific year), then the result will indicate the number of time units of the period in a regular single year. In other words, for an epoch of 2041-2060 and a monthly factor on a standard calendar with a days unit, the result will be c(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31). Leap days are thus only considered for the ⁠366_day⁠ and all_leap calendars.

Note that this function gives the number of time units in each level of the factor - the actual number of data points in the cf instance per factor level may be different. Use CFfactor_coverage() to determine the actual number of data points or the coverage of data points relative to the factor level.

Value

If f is a factor, a numeric vector with a length equal to the number of levels in the factor, indicating the number of time units in each level of the factor. If f is a list of factors, a list with each element a numeric vector as above.

Examples

cf <- CFtime("days since 2001-01-01", "365_day", 0:364)
f <- CFfactor(cf, "dekad")
CFfactor_units(cf, f)