DescTools (version 0.99.54)

axTicks.POSIXct: Compute Axis Tickmark Locations (For POSIXct Axis)

Description

Compute pretty tickmark locations, the same way as R does internally. By default, gives the at values which axis.POSIXct(side, x) would use.

Usage

axTicks.POSIXct(side, x, at, format, labels = TRUE, ...)
axTicks.Date(side = 1, x, ...)

Value

numeric vector of coordinate values at which axis tickmarks can be drawn.

Arguments

side

See axis.

x, at

A date-time or date object.

format

See strptime.

labels

Either a logical value specifying whether annotations are to be made at the tickmarks, or a vector of character strings to be placed at the tickpoints.

...

Further arguments to be passed from or to other methods.

Author

Andri Signorell <[e-mail]> simply copying R-Core code

Details

axTicks has no implementation for POSIXct axis. This function fills the gap.

See Also

axTicks, axis.POSIXct

Examples

with(beaver1, {
  time <- strptime(paste(1990, day, time %/% 100, time %% 100),
                   "%Y %j %H %M")
  plot(time, temp, type = "l") # axis at 4-hour intervals.
  # now label every hour on the time axis
  plot(time, temp, type = "l", xaxt = "n")
  r <- as.POSIXct(round(range(time), "hours"))
  axis.POSIXct(1, at = seq(r[1], r[2], by = "hour"), format = "%H")
  # place the grid
  abline(v=axTicks.POSIXct(1, at = seq(r[1], r[2], by = "hour"), format = "%H"),
         col="grey", lty="dotted")
})