Definitions of common eras and time scales.

eras() lists all available era definitions. eras(label) looks up a specific era by its unique, abbreviated name (e.g. "cal BP").

eras(label = NA)

Arguments

label

(Optional) Abbreviated names(s) of eras to look up.

Value

A table of era definitions. This can be passed to era() to construct an era object.

Details

Looking up eras by label uses partial matching.

See also

Other era definition functions: era

Examples

# List all available eras eras()
#> # A tibble: 32 x 6 #> label epoch name unit scale direction #> <chr> <dbl> <chr> <era_year> <int> <dbl> #> 1 BP 1950 Before Prese… Gregorian years (365.2425 days) 1.00e0 -1 #> 2 cal BP 1950 Before Prese… Gregorian years (365.2425 days) 1.00e0 -1 #> 3 BC 0 Before Christ Gregorian years (365.2425 days) 1.00e0 -1 #> 4 BCE 0 Before Commo… Gregorian years (365.2425 days) 1.00e0 -1 #> 5 AD 0 Anno Domini Gregorian years (365.2425 days) 1.00e0 1 #> 6 CE 0 Common Era Gregorian years (365.2425 days) 1.00e0 1 #> 7 a 1950 annum Gregorian years (365.2425 days) 1.00e0 -1 #> 8 ka 1950 kiloannum Gregorian years (365.2425 days) 1.00e3 -1 #> 9 Ma 1950 megaannum Gregorian years (365.2425 days) 1.00e6 -1 #> 10 Ga 1950 gigaannum Gregorian years (365.2425 days) 1.00e9 -1 #> # … with 22 more rows
# Look up a specific era by label eras("cal BP")
#> # A tibble: 1 x 6 #> label epoch name unit scale direction #> <chr> <dbl> <chr> <era_year> <int> <dbl> #> 1 cal BP 1950 Before Present Gregorian years (365.2425 days) 1 -1
# With partial matching eras("cal")
#> # A tibble: 1 x 6 #> label epoch name unit scale direction #> <chr> <dbl> <chr> <era_year> <int> <dbl> #> 1 cal BP 1950 Before Present Gregorian years (365.2425 days) 1 -1