Rounding to the nearest unit or multiple of a unit are supported. All meaningfull specifications in English language are supported - secs, min, mins, 2 minutes, 3 years etc.
round_date takes a date-time object and rounds it to the nearest value
of the specified time unit. For rounding date-times which is exactly halfway
between two consecutive units, the convention is to round up. Note that this
is in line with the behavior of R's base round.POSIXt function
but does not follow the convention of the base round function
which "rounds to the even digit" per IEC 60559.
floor_date takes a date-time object and rounds it down to the nearest
boundary of the specified time unit.
ceiling_date takes a date-time object and rounds it up to the nearest
boundary of the specified time unit.
round_date(x, unit = "second")floor_date(x, unit = "seconds")
ceiling_date(x, unit = "seconds", change_on_boundary = NULL)
a vector of date-time objects
a character string specifying the time unit or a multiple of a
unit to be rounded to. Valid base units are second, minute, hour, day,
week, month, bimonth, quarter, halfyear, or year. Arbitrary unique English
abbreviations as in period constructor are also
supported. Rounding to multiple of units (except weeks) is supported from
v1.6.0.
If NULL (the default) don't change instants on the
boundary (ceiling_date(ymd_hms('2000-01-01 00:00:00')) is
2000-01-01 00:00:00), but round up Date objects to the next
boundary (ceiling_date(ymd("2000-01-01"), "month") is
"2000-02-01"). When TRUE, instants on the boundary are
rounded up to the next boundary. When FALSE, date-time on the
boundary are never rounded up (this was the default for lubridate
prior to v1.6.0. See section Rounding Up Date Objects below
for more details.
By default rounding up Date objects follows 3 steps:
Convert to an instant representing lower bound of the Date:
2000-01-01 --> 2000-01-01 00:00:00
Round up to the next closest rounding unit boundary. For
example, if the rounding unit is month then next boundary
for 2000-01-01 will be 2000-02-01 00:00:00.
The motivation for this behavior is that 2000-01-01 is
conceptually an interval (2000-01-01 00:00:00 -- 2000-01-02
00:00:00) and the day hasn't started clocking yet at the exact
boundary 00:00:00. Thus, it seems wrong to round up a day to
its lower boundary.
If rounding unit is smaller than a day, return the instant from
step 2 above (POSIXct), otherwise return the Date
immediately following that instant.
The behavior on the boundary in the second step above can be changed by
setting change_on_boundary to a non-NULL value.
In lubridate rounding of a date-time objects tries to preserve the
class of the input object whenever it is meaningful. This is done by first
rounding to an instant and then converting to the original class by usual R
conventions.
# NOT RUN {
x <- as.POSIXct("2009-08-03 12:01:59.23")
round_date(x, "second")
round_date(x, "minute")
round_date(x, "5 mins")
round_date(x, "hour")
round_date(x, "2 hours")
round_date(x, "day")
round_date(x, "week")
round_date(x, "month")
round_date(x, "bimonth")
round_date(x, "quarter") == round_date(x, "3 months")
round_date(x, "halfyear")
round_date(x, "year")
x <- as.POSIXct("2009-08-03 12:01:59.23")
floor_date(x, "second")
floor_date(x, "minute")
floor_date(x, "hour")
floor_date(x, "day")
floor_date(x, "week")
floor_date(x, "month")
floor_date(x, "bimonth")
floor_date(x, "quarter")
floor_date(x, "halfyear")
floor_date(x, "year")
x <- as.POSIXct("2009-08-03 12:01:59.23")
ceiling_date(x, "second")
ceiling_date(x, "minute")
ceiling_date(x, "5 mins")
ceiling_date(x, "hour")
ceiling_date(x, "day")
ceiling_date(x, "week")
ceiling_date(x, "month")
ceiling_date(x, "bimonth") == ceiling_date(x, "2 months")
ceiling_date(x, "quarter")
ceiling_date(x, "halfyear")
ceiling_date(x, "year")
x <- ymd("2000-01-01")
ceiling_date(x, "month")
ceiling_date(x, "month", change_on_boundary = TRUE)
# }