seq.POSIXt               package:base               R Documentation

Generate Regular Sequences of Dates

Description:

     The methodw for 'seq' for date-time classes

Usage:

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

Arguments:

    from: starting date. Required

      to: end date. Optional. If supplied must be after 'from'.

      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.

Details:

     'by' can be specified in several ways.

        *  A number, taken to be in seconds.

        *  A object of class 'difftime'

        *  A character string, containing one of '"sec"', '"min"',
           '"hour"', '"day"', '"DSTday"', '"week"', '"month"' or
           '"year"'.  This can optionally be preceded by an integer and
           a space, or followed by '"s"'.

     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, but '"7
     DSTdays"') can be used as an alternative.  '"month"' and '"year"'
     allow for DST as from R 1.5.0.)

Value:

     A vector of class '"POSIXct"'.

See Also:

     'DateTimeClasses'

Examples:

     ## 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)
     ## quarters
     seq(ISOdate(1990,1,1), ISOdate(2000,1,1), by="3 months")
     ## days vs DSTdays
     seq(ISOdate(2000,3,20), by="day", length = 10)
     seq(ISOdate(2000,3,20), by="DSTday", length = 10)
     seq(ISOdate(2000,3,20), by="7 DSTdays", length = 4)

