.BG
.FN window
.TL
Window a Time-Series
.CS
window(x, start, end)
.AG x
time-series.  Missing values (`NA's) are allowed.
.AG start
optional new starting date for the series;  if earlier than start date
of `x', no change is made.
.AG end
optional new ending date for the series;  if later than end date of `x',
no change is made.
.PP
.RT
a time-series like `x' giving the data between the new
`start' and `end' dates.
.EX
sgnp <- window(gnp,c(1970,1),c(1975,12))
  #subseries of gnp from Jan 1970 through Dec 1975
.KW ts
.WR
