## Load Microsoft Data Set -
   x <- MSFT
## Aggregate by Weeks - 
   by <- timeSequence(from = start(x),  to = end(x), by = "week")
   aggregate(x, by, mean)
## Aggregate to Last Friday of Month -
   by <- unique(timeLastNdayInMonth(time(x), 5))
   X <- aggregate(x, by, mean)
   X
   dayOfWeek(time(X))
   isMonthly(X)
## Aggregate to Last Day of Quarter -
   by <- unique(timeLastDayInQuarter(time(x)))
   X <-  aggregate(x, by, mean)
   X
   isQuarterly(X)
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