month.distance {bsts}

Elapsed time in months

Description

The (integer) number of months between dates.

Usage

   MonthDistance(dates, origin)

Arguments

dates

A vector of class Date to be measured.

origin

A scalar of class Date.

Value

Returns a numeric vector giving the integer number of months that have elapsed between origin and each element in dates. The daily component of each date is ignored, so two dates that are in the same month will have the same measured distance. Distances are signed, so months that occur before origin will have negative values.

Author(s)

Steven L. Scott [e-mail]

Examples

  dates <- as.Date(c("2008-04-17",
                     "2008-05-01",
                     "2008-05-31",
                     "2008-06-01"))
  origin <- as.Date("2008-05-15")
  MonthDistance(dates, origin) ==  c(-1, 0, 0, 1)