| window {base} | R Documentation |
Time Windows
Description
window is a generic function which
extracts the subset of the object x
observed between the times start and end. If a
frequency is specified, the series is then re-sampled at the new
frequency.
Usage
window(x, ...)
window.default(x, start = NULL, end = NULL,
frequency = NULL, deltat = NULL, extend = FALSE, ...)
window.ts(x, start = NULL, end = NULL,
frequency = NULL, deltat = NULL, extend = FALSE, ...)
Arguments
x |
a time-series or other object. |
start |
the start time of the period of interest. |
end |
the end time of the period of interest. |
frequency, deltat |
the new frequency can be specified by either (or both if they are consistent). |
extend |
logical. If true, the |
... |
further arguments passed to or from other methods. |
Details
The start and end times can be specified as for ts. If
there is no observation at the new start or end,
the immediately following (start) or preceding (end)
observation time is used.
Value
The value depends on the method. window.default will return a
vector or matrix with an appropriate tsp attribute.
window.ts differs from window.default only in
ensuring the result is a ts object.
If extend = TRUE the series will be padded with NA if
needed.
See Also
time, ts.
Examples
data(presidents)
window(presidents, 1960, c(1969,4)) # values in the 1960's
window(presidents, deltat=1) # All Qtr1s
window(presidents, start=c(1945,3), deltat=1) # All Qtr3s
window(presidents, 1944, c(1979,2), extend=TRUE)