Tests whether an object is a vector of years with an era (a yr object).
is_yr() tests whether the object inherits from the S3 class era_yr.
is_valid_yr() performs additional checks to determine whether the object
is well-formed (see details).
validate_yr() throws an informative error message for invalid yrs.
Usage
is_yr(x)
validate_yr(x)
is_valid_yr(x)
Value
is_yr() and is_valid_yr() return TRUE or FALSE.
validate_yr() returns x invisibly, and is used for its side-effect of
throwing an informative error for invalid objects.
Arguments
x
Object to test.
Details
Valid yr objects:
Must contain numeric data (NAs are allowed)
Must have the era attribute set and not NA
Must not have more than one era
Must have an era attribute that is a valid era object (see validate_era())
See Also
Other era helper functions:
era_parameters,
era_year_parameters,
era_year,
era,
is_era_year(),
is_era(),
this_year()