[R] setting the steps for x axis labels on plot

[Chuck Cleland]

On 3/1/2010 6:16 AM, Gonzalo Garcia-Perate wrote:
> Hello, I'm new to R, I've been working with it for the last 2 weeks. I
> am plotting some data and not getting the labels on the x axis I am
> expecting on my plot.
> 
> 
> my code reads
> 
> #hours in the day
> h <- c(0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23)
> #hp is a data frame with a pivot table of 25 columns (label and data for
> 24 hours)
> plot(h, as.matrix(hp[1,2:25]), main = hp[1,1], type="l", xlim=c(0,23),
> ylim=c(0,1800), xlab="hour", ylab="visitor activity")
> 
> 
> the result you can see here:
> http://www.flickr.com/photos/gonzillaaa/4397357491/
> 
> I was hoping the steps on the x axis would be every hour or at least
> every two hours I am getting unevenly spaced steps (0, 5, 10, 20) instead.
> 
> 
> 
> apologies if this is too obvious a question, I've looked around on
> documentation etc. but found no reference to this.

  You can suppress the x axis in the call to plot() and then add it with
a call to axis().  For, example


plot(0:23, runif(24, min=0, max=1800), type="l", xlim=c(0,23),
ylim=c(0,1800), xlab="hour", ylab="visitor activity", xaxt='n')

axis(side=1, at=0:23, cex.axis=.5)

?axis

> Many thanks,
> 
> 
> Gonzalo.
> 
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-- 
Chuck Cleland, Ph.D.
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