## Overview

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.

If you are new to lubridate, the best place to start is the date and times chapter in R for data science.

## Installation

# The easiest way to get lubridate is to install the whole tidyverse:
install.packages("tidyverse")

# Alternatively, install just lubridate:
install.packages("lubridate")

# Or the the development version from GitHub:
# install.packages("devtools")
devtools::install_github("tidyverse/lubridate")

## Features

• Easy and fast parsing of date-times: ymd(), ymd_hms, dmy(), dmy_hms, mdy(), …

ymd(20101215)
#> [1] "2010-12-15"
mdy("4/1/17")
#> [1] "2017-04-01"
• Simple functions to get and set components of a date-time, such as year(), month(), mday(), hour(), minute() and second():

bday <- dmy("14/10/1979")
month(bday)
#> [1] 10
wday(bday, label = TRUE)
#> [1] Sun
#> Levels: Sun < Mon < Tue < Wed < Thu < Fri < Sat

year(bday) <- 2016
wday(bday, label = TRUE)
#> [1] Fri
#> Levels: Sun < Mon < Tue < Wed < Thu < Fri < Sat
• Helper functions for handling time zones: with_tz(), force_tz()

time <- ymd_hms("2010-12-13 15:30:30")
time
#> [1] "2010-12-13 15:30:30 UTC"

# Changes printing
with_tz(time, "America/Chicago")
#> [1] "2010-12-13 09:30:30 CST"

# Changes time
force_tz(time, "America/Chicago")
#> [1] "2010-12-13 15:30:30 CST"

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