Utilities for creation and manipulation of Interval objects.
Description
interval
creates an Intervalclass
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 datetimes 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 datetimes. int_diff
is similar to the POSIXt and Date
methods of diff
, but returns an Interval
object instead
of a difftime object.
Usage
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27  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)

Arguments
start 
a POSIXt or Date datetime object 
end 
a POSIXt or Date datetime 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 
by 
A period or duration object to shift by (for 
int1 
an Interval object (for 
int2 
an Interval object (for 
times 
A vector of POSIXct, POSIXlt or Date class datetimes (for

Details
Intervals are time spans bound by two real datetimes. 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.
Value
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 n1 intervals
between the n datetime in times
See Also
Intervalclass
, as.interval
, %within%
Examples
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42  interval(ymd(20090201), ymd(20090101))
date1 < as.POSIXct("20090308 01:59:59")
date2 < as.POSIXct("20000229 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("20010101"), ymd("20020101"))
int_start(int)
int_start(int) < ymd("20010601")
int
int < interval(ymd("20010101"), ymd("20020101"))
int_end(int)
int_end(int) < ymd("20020601")
int
int < interval(ymd("20010101"), ymd("20020101"))
int_length(int)
int < interval(ymd("20010101"), ymd("20020101"))
int_flip(int)
int < interval(ymd("20010101"), ymd("20020101"))
int_shift(int, duration(days = 11))
int_shift(int, duration(hours = 1))
int1 < interval(ymd("20010101"), ymd("20020101"))
int2 < interval(ymd("20010601"), ymd("20020601"))
int3 < interval(ymd("20030101"), ymd("20040101"))
int_overlaps(int1, int2) # TRUE
int_overlaps(int1, int3) # FALSE
int < interval(ymd("20020101"), ymd("20010101"))
int_standardize(int)
int1 < interval(ymd("20010101"), ymd("20020101"))
int2 < interval(ymd("20010601"), ymd("20020101"))
int3 < interval(ymd("20030101"), ymd("20040101"))
int_aligns(int1, int2) # TRUE
int_aligns(int1, int3) # FALSE
dates < now() + days(1:10)
int_diff(dates)
