Find or set sensible limits for Datetime axis — Datetime

Take a vector of Datetimes and return the start of the first and end of the last day of data. The start and the length can be adjusted by durations, like lubridate::ddays(). It is used in the gg_days() function to return a sensible x-axis. This function is a thin wrapper around lubridate::floor_date() and lubridate::ceiling_date().

Usage

Datetime_limits(
  x,
  start = NULL,
  length = NULL,
  unit = "1 day",
  midnight.rollover = FALSE,
  ...
)

Arguments

x: a vector of Datetimes
start: optional duration object, e.g. lubridate::ddays(1) that shifts the start of the Datetime vector by this amount.
length: optional duration object, e.g. lubridate::ddays(7) that shifts the end of the Datetime vector by this amount from the (adjusted) start. Depending on the data, you might have to subtract one day from the desired length to get the correct axis-scaling if you start at midnight.
unit: a character scalar giving the unit of rounding in lubridate::floor_date() and lubridate::ceiling_date()
midnight.rollover: a logical scalar indicating whether to rollover in cases of exact matches of rounded values and input values. Helpful if some cases fall exactly on the rounded values and others don`t.
...: other arguments passed to lubridate::floor_date() and lubridate::ceiling_date()

Value

a 2 item vector of Datetimes with the (adjusted) start and end of the input vector.

Examples

dataset <- c("2023-08-15", "2023-08-20")
breaks <- Datetime_breaks(dataset)
Datetime_limits(breaks)
#> [1] "2023-08-15 UTC" "2023-08-20 UTC"
Datetime_limits(breaks, start = lubridate::ddays(1))
#> [1] "2023-08-16 UTC" "2023-08-20 UTC"
Datetime_limits(breaks, length = lubridate::ddays(2))
#> [1] "2023-08-15 UTC" "2023-08-18 UTC"