| time {base} | R Documentation |
Sampling Times of Time-Series
Description
time, start, end and frequency are generic
functions with a default and a ts method (see
methods).
tsp(x) returns c(start(x),end(x),frequency(x)).
Usage
time(x, offset=0)
start(x)
end(x)
frequency(x)
tsp(x)
tsp(x) <- value
Arguments
x |
a time-series. |
Details
time creates the vector of times at which a time series was sampled.
offset can be used to indicate when sampling took place
in the time unit.
0 indicates the start of the unit, 0.5 the middle and
1 the end of the interval.
start and end extract
the times the first and last observations were taken
and frequency returns the number of samples per unit time.
tsp(x) returns the vector c(start(x),end(x),frequency(x)).
It is included for compatibility with the S language.
In the assignment form, value must be a numeric of length 3 or
NULL which removes the "tsp" attribute and the
"ts" class of x.
See Also
ts, window
and system.time for CPU usage.
Examples
data(presidents)
# a simple series plot
plot(c(time(presidents)), c(presidents), type="l")