An era
object defines the time scale associated with a vector of years
(see yr()
). 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
parameters.
era( label = character(), epoch = NULL, name = label, unit = era_year("Gregorian"), scale = 1, direction = -1 )
label | Character. If only one argument is given to |
---|---|
epoch | Numeric. Epoch year from which years are counted (in the Common Era). |
name | Character. Full name of the era. Defaults to the value of
|
unit | An |
scale | Integer. Number of years represented by one unit, e.g. |
direction | Are years counted backwards ( |
An object of class era
.
Other era definition functions:
eras()
Other era helper functions:
era_parameters
,
era_year_parameters
,
era_year
,
is_era_year()
,
is_era()
,
is_yr()
,
this_year()
era("cal BP")#> <era[1]> #> [1] Before Present (cal BP): Gregorian years (365.2425 days), counted backwards from 1950era("T.A.", epoch = -9021, name = "Third Age", direction = 1)#> <era[1]> #> [1] Third Age (T.A.): Gregorian years (365.2425 days), counted forwards from -9021