R: Compute Axis Tickmark Locations (For POSIXct Axis)

axTicks.POSIXct {DescTools} | R Documentation

## 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, ...)

### 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

### 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")
    })

[Package DescTools version 0.99.26 Index]