time                  package:base                  R Documentation

Sampling Times of Time Series

Description:

     `time' creates the vector of times at which a time series was
     sampled.

     `cycle' gives the positions in the cycle of each observation.

     `frequency' returns the number of samples per unit time and
     `deltat' the time interval between observations (see `ts').

Usage:

     time(x, offset=0, ...)
     cycle(x, ...)
     frequency(x, ...)
     deltat(x, ...)

Arguments:

       x: a univariate or multivariate time-series, or a vector or
          matrix.

  offset: can be used to indicate when sampling took place in the time
          unit. `0' (the default) indicates the start of the unit,
          `0.5' the middle and `1' the end of the interval.

     ...: extra arguments for future methods.

Details:

     These are all generic functions, which will use the `tsp'
     attribute of `x' if it exists. `time' and `cycle' have methods for
     class `ts' that coerce the result to that class.

See Also:

     `ts', `start', `tsp', `window'.

     `date' for clock time, `system.time' for CPU usage.

Examples:

     data(presidents)
     cycle(presidents)
     # a simple series plot: c() makes the x and y arguments into vectors
     plot(c(time(presidents)), c(presidents), type="l")

