component_extract: Extracting components from messy dates

In messydates: A Flexible Class for Messy Dates

Extracting components from messy dates

Description

These functions allow the extraction of particular date components from messy dates, such as the year(), month(), day(), and, for date-times, hour(), minute(), second(), and the time zone (tz()).

These are methods for the same-named generics in {lubridate}, so they extend rather than mask them: calling e.g. year() on an mdate returns the messy-date-aware result (understanding partial precision such as 2012-06-XX), while calling it on a Date or POSIXct still dispatches to {lubridate}'s own methods. This lets {messydates} and {lubridate} be loaded together, in either order, without one masking the other.

precision() allows for the identification of the greatest level of precision in (currently) the first element of each date.

Usage

## S3 method for class 'mdate'
year(x, ...)

## S3 method for class 'mdate'
month(x, ...)

## S3 method for class 'mdate'
mday(x, ...)

## S3 method for class 'mdate'
hour(x, ...)

## S3 method for class 'mdate'
minute(x, ...)

## S3 method for class 'mdate'
second(x, ...)

## S3 method for class 'mdate'
tz(x, ...)

precision(x)

## S3 method for class 'mdate'
precision(x)

Arguments

x	A mdate object
...	Additional arguments passed to or from other methods (accepted for compatibility with the {lubridate} generics; unused).

Details

Unlike {lubridate}'s tz(), which returns an Olson time zone name, tz.mdate() returns the ISO 8601 UTC offset designator carried by the date-time string ("Z" or e.g. "+02:00"), or NA when none is present.

Value

year(), month(), day(), hour(), minute(), and second() extraction return the integer for the requested component (NA where the component is absent or unspecified).

tz() returns the time zone designator or offset as a string.

precision() returns the level of greatest precision for each date.

Precision

Date precision is measured relative to the day in 1/days(x). That is, a date measured to the day will return a precision score of 1, a date measured to the month will return a precision score of between 1/28 and 1/31, and annual measures will have a precision of between 1/365 and 1/366. Times of day extend the same scale below the day: a date-time measured to the hour returns 24, to the minute 1440, and to the second 86400.

Examples

year(as_messydate(c("2012-02-03","2012","2012-02")))
month(as_messydate(c("2012-02-03","2012","2012-02")))
day(as_messydate(c("2012-02-03","2012","2012-02")))
hour(as_messydate(c("2012-02-03 14:30:00","2012-02-03")))
minute(as_messydate("2012-02-03 14:30:00"))
second(as_messydate("2012-02-03 14:30:05"))
tz(as_messydate("2012-02-03 14:30:00+02:00"))
precision(as_messydate(c("2012-02-03","2012","2012-02")))
precision(as_messydate("2012-02-03 14:30"))

messydates documentation built on July 17, 2026, 1:07 a.m.