[R] R:plot and dots

[Marc Schwartz (via MN)]

On Thu, 2005-07-21 at 16:18 +0200, Clark Allan wrote:
> hi all
> 
> a very simple question.
> 
> i have plot(x,y)
> 
> but i would like to add in on the plot the observation number associated
> with each point.
> 
> how can this be done?
> 
> /
> allan

If you mean the unique observation number associated with each x,y pair,
you can use:

  text(x, y, labels = ObsNumberVector, pos = 3)

after the plot(x, y) call:

 df <- data.frame(x = rnorm(10), y = rnorm(10), ID = 1:10)
 with(df, plot(x, y))
 with(df, text(x, y, labels = ID, pos = 3))

See ?text for more information.  Note that I used pos = 3 which places
the label above the data point. There are other positioning parameters
available, which are noted in the help file.

Note also that you might have to adjust the plot axis limits depending
upon where you place the text and your extreme points.

If you mean the frequency of each x,y pair (if there is more than one
observation per x,y pair), you might want to review Deepayan's recent
post here:

https://stat.ethz.ch/pipermail/r-help/2005-July/074042.html

HTH,

Marc Schwartz