duration {lubridate} | R Documentation

## Create a duration object.

### Description

`duration()` creates a duration object with the specified values. Entries for different units are cumulative. durations display as the number of seconds in a time span. When this number is large, durations also display an estimate in larger units,; however, the underlying object is always recorded as a fixed number of seconds. For display and creation purposes, units are converted to seconds using their most common lengths in seconds. Minutes = 60 seconds, hours = 3600 seconds, days = 86400 seconds, weeks = 604800. Units larger than weeks are not used due to their variability.

### Usage

    duration(num = NULL, units = "seconds", ...)

    dseconds(x = 1)

    dminutes(x = 1)

    dhours(x = 1)

    ddays(x = 1)

    dweeks(x = 1)

    dyears(x = 1)

    dmilliseconds(x = 1)

    dmicroseconds(x = 1)

    dnanoseconds(x = 1)

    dpicoseconds(x = 1)

    is.duration(x)

### Arguments

`num` | the number or a character vector of time units. In string representation all unambiguous name units and abbreviations and ISO 8601 formats are supported; 'm' stands for month and 'M' for minutes unless ISO 8601 "P" modifier is present (see examples). Fractional units are supported.
`units` | a character string that specifies the type of units that num refers to. When `num` is character, this argument is ignored.
`...` | a list of time units to be included in the duration and their amounts. Seconds, minutes, hours, days, and weeks are supported.
`x` | numeric value of the number of units to be contained in the duration.

### Details

Durations record the exact number of seconds in a time span. They measure the exact passage of time but do not always align with measurements made in larger units of time such as hours, months and years. This is because the length of larger time units can be affected by conventions such as leap years and Daylight Savings Time. Base R provides a second class for measuring durations, the difftime class.

Duration objects can be easily created with the helper functions `dweeks()`, `ddays()`, `dminutes()`, `dseconds()`. These objects can be added to and subtracted to date- times to create a user interface similar to object oriented programming.

### Value

a duration object

### See Also

`as.duration()` Duration

### Examples

    ### Separate period and units vectors

    duration(90, "seconds")
    duration(1.5, "minutes")
    duration(-1, "days")

    ### Units as arguments

    duration(day = -1)
    duration(second = 90)
    duration(minute = 1.5)
    duration(mins = 1.5)
    duration(second = 3, minute = 1.5, hour = 2, day = 6, week = 1)
    duration(hour = 1, minute = -60)

    ### Parsing

    duration("2M 1sec")
    duration("2hours 2minutes 1second")
    duration("2d 2H 2M 2S")
    duration("2days 2hours 2mins 2secs")
    # Missing numerals default to 1. Repeated units are added up.
    duration("day day")

    ### ISO 8601 parsing

    duration("P3Y6M4DT12H30M5S")
    duration("P23DT23H") # M stands for months
    duration("10DT10M") # M stands for minutes
    duration("P23DT60H 20min 100 sec") # mixing ISO and lubridate style parsing

    # Comparison with characters (from v1.6.0)

    duration("day 2 sec") > "day 1sec"

    ## ELEMENTARY CONSTRUCTORS:

    dseconds(1)
    dminutes(3.5)

    x <- ymd_hms("2009-08-03", tz="America/Chicago")
    x + ddays(1) + dhours(6) + dminutes(30)
    x + ddays(100) - dhours(8)

    class(as.Date("2009-08-09") + ddays(1)) # retains Date class
    as.Date("2009-08-09") + dhours(12)
    class(as.Date("2009-08-09") + dhours(12))
    # converts to POSIXt class to accomodate time units

    dweeks(1) - ddays(7)
    c(1:3) * dhours(1)

    # compare DST handling to durations
    boundary <- ymd_hms("2009-03-08 01:59:59", tz="America/Chicago")
    boundary + days(1) # period
    boundary + ddays(1) # duration
    is.duration(as.Date("2009-08-03")) # FALSE
    is.duration(duration(days = 12.4)) # TRUE

[Package lubridate version 1.7.4 Index]