Functions for extracting or assigning the era of a vector of years.
This function does not alter the underlying values of
to convert the values of a
yr vector to a new era.
yr_era(x) yr_set_era(x, era) yr_era(x) <- value
A vector of years.
yr_era(x) returns the existing era associated with
yr_set_era(x, era) and
yr_era(x) <- era return
x with the new era
x is not already a
yr vector, it will attempt to coerce it
x <- 5000:5050 yr_era(x) <- era("cal BP") yr_era(x)#> <era> #>  Before Present (cal BP): Gregorian years (365.2425 days), counted backwards from 1950