seq.POSIXt {base}R Documentation

Generate Regular Sequences of Dates


The method for seq for date-time classes.


## S3 method for class 'POSIXt':
seq(from, to, by, length.out = NULL, along.with = NULL, ...)


from starting date. Required.
to end date. Optional.
by increment of the sequence. Optional. See Details.
length.out integer, optional. desired length of the sequence.
along.with take the length from the length of this argument.
... arguments passed to or from other methods.


by can be specified in several ways.

The difference between "day" and "DSTday" is that the former ignores changes to/from daylight savings time and the latter takes the same clock time each day. ("week" ignores DST (it is a period of 144 hours), but "7 DSTdays") can be used as an alternative. "month" and "year" allow for DST.)

The timezone of the result is taken from from: remember than GMT does not have daylight savings time.

Using "month" first advances the month without changing the day: if this results in an invalid day of the month, it is counted forward into the next month: see the examples.


A vector of class "POSIXct".

See Also



## first days of years
seq(ISOdate(1910,1,1), ISOdate(1999,1,1), "years")
## by month
seq(ISOdate(2000,1,1), by = "month", length = 12)
seq(ISOdate(2000,1,31), by = "month", length = 4)
## quarters
seq(ISOdate(1990,1,1), ISOdate(2000,1,1), by = "3 months")
## days vs DSTdays: use c() to lose the timezone.
seq(c(ISOdate(2000,3,20)), by = "day", length = 10)
seq(c(ISOdate(2000,3,20)), by = "DSTday", length = 10)
seq(c(ISOdate(2000,3,20)), by = "7 DSTdays", length = 4)

[Package base version 2.5.0 Index]