Date-time must be a POSIXct, POSIXlt, Date, Period, chron, yearmon, yearqtr, zoo, zooreg, timeDate, xts, its, ti, jul, timeSeries, and fts objects.
hour(x) hour(x) <- value
a date-time object
numeric value to be assigned to the
the hours element of x as a decimal number
x <- ymd("2012-03-26") hour(x)#>  0hour(x) <- 1 hour(x) <- 25 hour(x) > 2#>  FALSE