[R] How to show the intermediate tick marks without the values in a different color

[Marc Schwartz]

On Thu, 2006-03-02 at 20:06 -0600, xpRt.wannabe wrote:
> Is there a way to show also the intermediate tick marks without the
> values?
> 
> Example:
> 
> plot(cars)
> 
> What would one do to show the tick marks in, say, gray color at the
> increment of 1 without showing the actual values in-between the default
> x
> values: 5, 10, 15, 20, 25?

Try this:

 # Do the plot without the x axis
 plot(cars, xlim = c(0, 25), xaxt = "n")

 # Do the x axis in grey with tick marks at 0:25
 # without labels
 axis(1, at = 0:25, labels = NA, col = "grey")

 # Now do the default tick marks in black with labels
 axis(1)


See ?plot.default, ?par (for 'xaxt') and ?axis for more information.

HTH,

Marc Schwartz