lubridate

Date-time data can be frustrating to work with in R. R commands for date-times are generally unintuitive and change depending on the type of date-time object being used. Moreover, the methods we use with date-times must be robust to time zones, leap days, daylight savings times, and other time related quirks, and R lacks these capabilities in some situations. Lubridate makes it easier to do the things R does with date-times and possible to do the things R does not. Specifically, lubridate provides:

• a set of intuitive date-time related functions that work the same way for all common date-time classes (including those from chron, timeDate, zoo, xts, its, tis, timeSeries, fts, and tseries)

• quick and easy parsing of date-times: ymd(), dmy(), mdy(), ...

• simple functions to extract and modify components of a date-time, such as years, months, days, hours, minutes, and seconds: year(), month(), day(), ...

• helper functions for handling time zones: with_tz(), force_tz()

Lubridate also expands the type of mathematical operations that can be performed with date-time objects. It introduces three new time span classes borrowed from http://joda.org.

• durations, which measure the exact amount of time between two points

• periods, which accurately track clock times despite leap years, leap seconds, and day light savings time

• intervals, a protean summary of the time information between two points