era object defines the time scale associated with a vector of years
era() returns an
era object, either by looking up
label in the standard eras defined in
eras() or, if more than one
argument is given, constructing a new definition with the specified
era( label = character(), epoch = NULL, name = label, unit = era_year("Gregorian"), scale = 1, direction = -1 )
Character. If only one argument is given to
Numeric. Epoch year from which years are counted (in the Common Era).
Character. Full name of the era. Defaults to the value of
Integer. Number of years represented by one unit, e.g.
Are years counted backwards (
An object of class
Other era definition functions:
era("cal BP")#> <era> #>  Before Present (cal BP): Gregorian years (365.2425 days), counted backwards from 1950era("T.A.", epoch = -9021, name = "Third Age", direction = 1)#> <era> #>  Third Age (T.A.): Gregorian years (365.2425 days), counted forwards from -9021