| period {lubridate} | R Documentation |
period creates a period object with the specified values. period
provides the behaviour of period in a way that is more
suitable for automating within a function.
period(num = NULL, units = "second", ...) is.period(x)
num |
a numeric vector that lists the number of time units to be
included in the period. From v1.6.0 |
units |
a character vector that lists the type of units to be used. The
units in units are matched to the values in num according to their
order. When |
... |
a list of time units to be included in the period and their
amounts. Seconds, minutes, hours, days, weeks, months, and years are
supported. Normally only one of |
x |
an R object |
Within a Period object, time units do not have a fixed length (except for seconds) until they are added to a date-time. The length of each time unit will depend on the date-time to which it is added. For example, a year that begins on 2009-01-01 will be 365 days long. A year that begins on 2012-01-01 will be 366 days long. When math is performed with a period object, each unit is applied separately. How the length of a period is distributed among its units is non-trivial. For example, when leap seconds occur 1 minute is longer than 60 seconds.
Periods track the change in the "clock time" between two date-times. They are measured in common time related units: years, months, days, hours, minutes, and seconds. Each unit except for seconds must be expressed in integer values.
Period objects can be easily created with the helper functions
years, months, weeks,
days, hours, minutes,
and seconds. These objects can be added to and subtracted
to date-times to create a user interface similar to object oriented programming.
Note: Arithmetic with periods can results in undefined behavior when
non-existent dates are involved (such as February 29th). Please see
Period-class for more details and %m+% and
add_with_rollback for alternative operations.
a period object
Period-class, quick_periods,
%m+%, add_with_rollback
period(c(90, 5), c("second", "minute"))
# "5M 90S"
period(-1, "days")
period(c(3, 1, 2, 13, 1), c("second", "minute", "hour", "day", "week"))
period(c(1, -60), c("hour", "minute"))
period(0, "second")
period (second = 90, minute = 5)
period(day = -1)
period(second = 3, minute = 1, hour = 2, day = 13, week = 1)
period(hour = 1, minute = -60)
period(second = 0)
period(c(1, -60), c("hour", "minute"), hour = c(1, 2), minute = c(3, 4))
period("2M 1sec")
period("2hours 2minutes 1second")
period("2d 2H 2M 2S")
period("2days 2hours 2mins 2secs")
# Missing numerals default to 1. Repeated units are added up.
duration("day day")
# Comparison with characters is supported from v1.6.0.
duration("day 2 sec") > "day 1sec"
is.period(as.Date("2009-08-03")) # FALSE
is.period(period(months= 1, days = 15)) # TRUE