[R] quick legend() question

[Marc Schwartz]

On Thu, 2007-03-22 at 15:47 +0000, Robin Hankin wrote:
> Hi
> 
> I have a scatterplot of points with pch=1 and a single point with  
> pch=3, lwd=3.
> It has a high line width to attract attention to it.
> 
> The following script
> 
> 
> 
> plot(rnorm(10),rnorm(10),col="black")
> points(rnorm(10),rnorm(10),col="red")
> points(0,0,pch=3,lwd=3)
> 
> 
> if(TRUE){
>    legend("bottomleft",c("a","b","Truth"),pch=c(1,1,3),col=c 
> ("black","red","black"))
> } else {
>    legend("bottomleft",c("a","b","Truth"),pch=c(1,1,3),col=c 
> ("black","red","black"),lwd=c(0,0,3))
> }
> 
> 
> doesn't quite work as desired:  the third symbol in the legend is not  
> the right line width.
> 
> Replacing TRUE with FALSE doesn't work as desired either; the first two
> symbols end up with a line I don't want.
> The same happens with lwd=c(NA,NA,3).
> 
> How to coerce legend()   into doing what I want?

Robin,

Is this what you want?


plot(rnorm(10), rnorm(10), col = "black")

points(rnorm(10), rnorm(10), col = "red")

points(0, 0, pch = 3, lwd = 3)

legend("bottomleft", c("a", "b", "Truthiness"), pch = c(1, 1, 3), 
       col = c("black", "red", "black"), lwd = c(0, 0, 3), 
       lty = c(0, 0, 1))


Add 'lty' to the legend() call so that the line types for the first two
symbols are set to 'blank'.

HTH,

Marc Schwartz