POSIXct

Create

Action	Code	Details
From ymd	ISOdate(year, month, day)
From ymd	lubridate::make_date(year, month, day) |> as.POSIXct()
From ymdhms	ISOdatetime(year, month, day, hour, minute, second)
From ymdhms	lubridate::make_datetime(year, month, day, hour, min, sec)
From ymdhms in UTC timezone	ISOdatetime(years, months, days, hours, minutes, seconds, tz = 'UTC')
Current date in UTC	Sys.Date() |> as.POSIXct()
Current datetime	Sys.time()
Current datetime	lubridate::now()
Current datetime in UTC timezone	lubridate::now(tzone = 'UTC')
Unix epoch	as.POSIXct(0)
From total seconds since Unix epoch	as.POSIXct(n)
From total seconds since reference date	as.POSIXct(n, origin = ref_date)
Datetime from YYYY-MM-DD string	as.POSIXct(x)
Datetime from YYYY-MM-DD HH:mm:ss string	as.POSIXct(x)
Date from DD-MM-YYYY string	as.POSIXct(x, format = '%d-%m-%Y')

Test

Action	Code	Details
Is POSIXt	inherits(x, 'POSIXt')
Is POSIXt	lubridate::is.POSIXt(x)
Is POSIXct	inherits(x, 'POSIXct')
Is POSIXct	lubridate::is.POSIXct(x)
Same date	x == y
Happens before y	x < y
Happens after y	x > y

Extract

Action	Code	Details
Days from Unix epoch	as.Date(x) |> as.integer()
Seconds from Unix epoch (timestamp)	as.integer(x)
Year	lubridate::year(x)
Month	lubridate::month(x)
Day	lubridate::day(x)
Week number (1-53)	lubridate::week(x)
ISO week number (1-52)	lubridate::isoweek(x)
Weekday number	lubridate::wday(x, week_start = 1)	Mon=1, Sun=7
Hour	lubridate::hour(x)
Minute	lubridate::minute(x)
Second	lubridate::second(x)

Derive

Action	Code	Details
Shift forward by n days	x + n * 86400
Shift forward by n days	x + lubridate::days(n)
Shift forward by n seconds	x + n
Shift forward by a specific ymdhms period	x + lubridate::period(year, month, day, hour, minute, second)
Truncate to date	trunc(x, 'days') |> as.POSIXct()	Drops the time component, falling back to midnight 00:00:00
Truncate to hours	trunc(x, 'hours') |> as.POSIXct()
Truncate to minutes	trunc(x, 'mins') |> as.POSIXct()

Convert

Action	Code	Details
To Date	as.Date(x)
To POSIXlt	as.POSIXlt(x)

Format as string

Action	Code	Details
Format as ISO datetime (yyyy-mm-dd HH:MM:SS.SSS)	as.character(x)
Format as yyyy-mm-dd HH:MM:SS	format(x)
Format as yyyy-mm-dd	format(d, '%Y-%m-%d')
Format as dd-mm-yyyy	format(d, '%d-%m-%Y')
Format in system locale	format(x, '%a %b %d')