Resolves messy dates into an extrema

This collection of S3 methods 'resolve' messy dates into a single date according to some explicit bias, such as returning the minimum or maximum date, the mean, median, or modal date, or a random date from among the possible resolutions for each messy date. If the date is not 'messy' (i.e. has no annotations) then just that precise date is returned. This can be useful for various descriptive or inferential projects.

Usage

vmin(..., na.rm = FALSE)

# S3 method for class 'mdate'
vmin(..., na.rm = FALSE)

# S3 method for class 'mdate'
min(..., na.rm = FALSE)

vmax(..., na.rm = FALSE)

# S3 method for class 'mdate'
vmax(..., na.rm = FALSE)

# S3 method for class 'mdate'
max(..., na.rm = FALSE)

Arguments

...

a mdate object

na.rm

Should NAs be removed? FALSE by default.

Value

A single scalar or vector of dates

Details

vmin()/min() and vmax()/max() work directly on the annotated string (dropping ~/?/% and, for vmax()/max(), filling in unspecified X components) rather than via expand(), which makes them considerably faster than resolving through the full expanded set. min() and max() further resolve a vector to a single, overall extremum (matching the usual behaviour of these generics), while vmin() and vmax() resolve each element separately.

Dates that carry a time of day are already precise and so pass through these functions unchanged, keeping their time; a time of day plays no further role in choosing the minimum or maximum.

Examples

d <- as_messydate(c("2008-03-25", "?2012-02-27", "2001-01?", "2001~",
  "2001-01-01..2001-02-02", "{2001-01-01,2001-02-02}",
  "{2001-01,2001-02-02}", "2008-XX-31", "-0050-01-01"))
d
#>  'mdate' chr [1:9] "2008-03-25" "?2012-02-27" "2001-01?" "~2001" ...
# a precise date-time is returned unchanged
vmin(as_messydate("2012-01-01 14:30:00"))
#>  'mdate' chr "2012-01-01 14:30:00"
vmin(d)
#>  'mdate' chr [1:9] "2008-03-25" "2012-02-27" "2001-01-01" "2001-01-01" ...
min(d)
#>  'mdate' chr "-0050-01-01"
vmax(d)
#>  'mdate' chr [1:9] "2008-03-25" "2012-02-27" "2001-01-31" "2001-12-31" ...
max(d)
#>  'mdate' chr "2012-02-27"