Rollback of Months
Generating regular sequences of times with the help of
seq.POSIXt can have undesirable effects. This function
“first advances the month without changing the day: if this results
in an invalid day of the month, it is counted forward into the next month”.
Monthly or yearly sequences starting at the end of a month with 30 or 31
days (or 29 in case of a leap year) therefore do not always fall on the end
of shorter months. rollback reverts this process by counting the days
backwards again.
rollback(.dateTime, periodicity)
.dateTime |
A |
periodicity |
A character string specifying a multiple of month(s) or
year(s). See |
Returns a POSIXct vector.
# rollback monthly time series
by <- "1 month"
rollback(
.dateTime = seq(
from = as.POSIXct("2000-01-31", tz = "UTC"),
to = as.POSIXct("2000-12-31", tz = "UTC"),
by = by
),
periodicity = by
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