# axTicks.POSIXct: Compute Axis Tickmark Locations (For POSIXct Axis) In AndriSignorell/DescTools: Tools for Descriptive Statistics

## 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

 ```1 2 3``` ```axTicks.POSIXct(side, x, at, format, labels = TRUE, ...) axTicks.Date(side = 1, x, ...) ```

## 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.

## Details

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

## Value

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

## Author(s)

Andri Signorell <andri@signorell.net> simply copying R-Core code

`axTicks`, `axis.POSIXct`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12``` ```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") }) ```