[R] Hmisc errbar color

[David Winsemius]

On Feb 9, 2011, at 8:27 PM, Robert Baer wrote:

> Is there an easy way to make the error bars the same color as the  
> points and lines they are plotted with.
>
> My example
> # fake data
> x=sample(1:10, 100, replace =T)
> y = rnorm(100) + runif(100)
> df=data.frame(x,y)
> # summarize data
> m = aggregate(df,list(x),mean)
> se = aggregate(df,list(x),sd)/sqrt(10)
> library(Hmisc)
> plot(x,y)
> errbar(m$x, m$y, m$y+1.96*se$y, m$y-1.96*se 
> $y,col='red',cex=2,type='b',add=TRUE)

If you look at the errbar code you see that it is not lattice (yet?)  
but rather base graphics based. The bars appear to be drawn with  
segments() and the arguments to segments (from its help page:

segments(x0, y0, x1 = x0, y1 = y0, col = par("fg"), lty = par("lty"),  
lwd = par("lwd"), ...)
So I would think you should be trying to use par(fg="red"). (I know  
you didn't ask but the large solid red points at the means strike me  
as ugly. My suggestion would be open diamonds achieved with pch=23)
  par(fg="red")
  errbar(m$x, m$y, m$y+1.96*se$y, m$y-1.96*se 
$y,col='red',cex=2,type='b',add=TRUE, pch=23)
  par(fg="black")

-- 
David Winsemius, MD
West Hartford, CT