annotate: Annotates dates as censored, uncertain, or approximate

annotateR Documentation

Annotates dates as censored, uncertain, or approximate


Some datasets have for example an arbitrary cut off point for start and end points, but these are often coded as precise dates when they are not necessarily the real start or end dates. This collection of functions helps annotate uncertainty and approximation to dates according to ISO2019E standards. Inaccurate start or end dates can be represented by an affix indicating "on or before", if used as a prefix (e.g. ..1816-01-01), or indicating "on or after", if used as a suffix (e.g. 2016-12-31..). Approximate dates are indicated by adding a tilde to year, month, or day components, as well as groups of components or whole dates to estimate values that are possibly correct (e.g. 2003-03-03~). Day, month, or year, uncertainty can be indicated by adding a question mark to a possibly dubious date (e.g. 1916-10-10?) or date component (e.g. 1916-?10-10).




as_approximate(x, component = NULL)

as_uncertain(x, component = NULL)



A date vector


Annotation can be added on specific date components ("year", "month" or "day"), or to groups of date components (month and day ("md"), or year and month ("ym")). This must be specified. If unspecified, annotation will be added after the date (e.g. 1916-10-10?), indicating the whole date is uncertain or approximate. For specific date components, uncertainty or approximation is annotated to the left of the date component. E.g. for "day": 1916-10-?10 or 1916-10-~10. For groups of date components, uncertainty or approximation is annotated to the right of the group ("ym") or to both components ("md"). E.g. for "ym": 1916-10~-10; for "md": 1916-?10-?10.


A mdate object with annotated date(s)


  • on_or_before(): prefixes dates with ".." where start date is uncertain

  • on_or_after(): suffixes dates with ".." where end date is uncertain

  • as_approximate(): adds tildes to indicate approximate dates/date components

  • as_uncertain(): adds question marks to indicate dubious dates/date components.


data <- data.frame(Beg = c("1816-01-01", "1916-01-01", "2016-01-01"),
  End = c("1816-12-31", "1916-12-31", "2016-12-31"))
dplyr::mutate(data, Beg = ifelse(Beg <= "1816-01-01",
  on_or_before(Beg), Beg))
dplyr::mutate(data, End = ifelse(End >= "2016-01-01",
  on_or_after(End), End))
dplyr::mutate(data, Beg = ifelse(Beg == "1916-01-01",
  as_approximate(Beg), Beg))
dplyr::mutate(data, End = ifelse(End == "1916-12-31",
  as_uncertain(End), End))

messydates documentation built on Jan. 22, 2023, 1:36 a.m.