`Interval`

objects.`interval`

creates an `Interval-class`

object with the
specified start and end dates. If the start date occurs before the end date,
the interval will be positive. Otherwise, it will be negative.

`%--%`

Creates an interval that covers the range spanned by two
dates. It replaces the original behavior of lubridate, which created an
interval by default whenever two date-times were subtracted.

`int_start`

and `int_start<-`

are accessors the start date of an
interval. Note that changing the start date of an interval will change the
length of the interval, since the end date will remain the same.

`int_flip`

reverses the order of the start date and end date in an
interval. The new interval takes place during the same timespan as the
original interval, but has the opposite direction.

`int_shift`

shifts the start and end dates of an interval up or down the
timeline by a specified amount. Note that this may change the exact length of
the interval if the interval is shifted by a Period object. Intervals shifted
by a Duration or difftime object will retain their exact length in seconds.

`int_overlaps`

tests if two intervals overlap.

`int_standardize`

ensures all intervals in an interval object are
positive. If an interval is not positive, flip it so that it retains its
endpoints but becomes positive.

`int_aligns`

tests if two intervals share an endpoint. The direction of
each interval is ignored. int_align tests whether the earliest or latest
moments of each interval occur at the same time.

`int_diff`

returns the intervals that occur between the elements of a
vector of date-times. `int_diff`

is similar to the POSIXt and Date
methods of `diff`

, but returns an `Interval`

object instead
of a difftime object.

`interval(start, end, tzone = attr(start, "tzone"))`start %--% end

is.interval(x)

int_start(int)

int_start(int) <- value

int_end(int)

int_end(int) <- value

int_length(int)

int_flip(int)

int_shift(int, by)

int_overlaps(int1, int2)

int_standardize(int)

int_aligns(int1, int2)

int_diff(times)

start

a POSIXt or Date date-time object

end

a POSIXt or Date date-time object

tzone

a recognized timezone to display the interval in

x

an R object

int

an interval object

value

interval's start/end to be assigned to `int`

by

A period or duration object to shift by (for `int_shift`

)

int1

an Interval object (for `int_overlaps`

, `int_aligns`

)

int2

an Interval object (for `int_overlaps`

, `int_aligns`

)

times

A vector of POSIXct, POSIXlt or Date class date-times (for
`int_diff`

)

`interval`

- `Interval`

object.

`int_start`

and `int_end`

return a POSIXct date object when
used as an accessor. Nothing when used as a setter.

`int_length`

- numeric length of the interval in
seconds. A negative number connotes a negative interval.

`int_flip`

- flipped interval object

`int_shift`

- interval object

`int_overlaps`

logical, TRUE if int1 and int2 overlap by at
least one second. FALSE otherwise

`int_align`

logical, TRUE if int1 and int2 begin or end on the
same moment. FALSE otherwise

`int_diff`

- interval object that contains the n-1 intervals
between the n date-time in times

Intervals are time spans bound by two real date-times. Intervals can be
accurately converted to either period or duration objects using
`as.period`

, `as.duration`

. Since an interval is
anchored to a fixed history of time, both the exact number of seconds that passed
and the number of variable length time units that occurred during the interval can be
calculated.

# NOT RUN { interval(ymd(20090201), ymd(20090101)) date1 <- as.POSIXct("2009-03-08 01:59:59") date2 <- as.POSIXct("2000-02-29 12:00:00") interval(date2, date1) interval(date1, date2) span <- interval(ymd(20090101), ymd(20090201)) is.interval(period(months= 1, days = 15)) # FALSE is.interval(interval(ymd(20090801), ymd(20090809))) # TRUE int <- interval(ymd("2001-01-01"), ymd("2002-01-01")) int_start(int) int_start(int) <- ymd("2001-06-01") int int <- interval(ymd("2001-01-01"), ymd("2002-01-01")) int_end(int) int_end(int) <- ymd("2002-06-01") int int <- interval(ymd("2001-01-01"), ymd("2002-01-01")) int_length(int) int <- interval(ymd("2001-01-01"), ymd("2002-01-01")) int_flip(int) int <- interval(ymd("2001-01-01"), ymd("2002-01-01")) int_shift(int, duration(days = 11)) int_shift(int, duration(hours = -1)) int1 <- interval(ymd("2001-01-01"), ymd("2002-01-01")) int2 <- interval(ymd("2001-06-01"), ymd("2002-06-01")) int3 <- interval(ymd("2003-01-01"), ymd("2004-01-01")) int_overlaps(int1, int2) # TRUE int_overlaps(int1, int3) # FALSE int <- interval(ymd("2002-01-01"), ymd("2001-01-01")) int_standardize(int) int1 <- interval(ymd("2001-01-01"), ymd("2002-01-01")) int2 <- interval(ymd("2001-06-01"), ymd("2002-01-01")) int3 <- interval(ymd("2003-01-01"), ymd("2004-01-01")) int_aligns(int1, int2) # TRUE int_aligns(int1, int3) # FALSE dates <- now() + days(1:10) int_diff(dates) # }