Change your two lines > arrows(xvals, mean, xvals, CI.H, angle=90,length=length) > arrows(xvals, mean, xvals, CI.L, angle=90,length=length) to the one line arrows(xvals, mean, xvals, mean + sign(mean) * se, angle=90, length=length)
(I would also use a scatter plot instead of a barplot for this sort of thing and draw both error bars. I think the bars give a misleading impression of what is going on.) Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf > Of raz > Sent: Wednesday, November 27, 2013 7:23 AM > To: r-help@r-project.org > Subject: [R] Conditional error bars > > How can I condition any error bar function that use the arrows() function, > such as 'CI.plot' (see example below) or 'error.bars', to draw only upper > error bar (upper CI) if the bar value (mean) is positive and the lower > error bar (lower CI) if bar value is negative? > > CI.plot <- function(mean, se,length, ylim=c(-5, max(CI.H)), ...) { > CI.H <- mean+se > CI.L <- mean-se > xvals <- barplot(mean, ylim=ylim, ...) # Plot bars > arrows(xvals, mean, xvals, CI.H, angle=90,length=length) > arrows(xvals, mean, xvals, CI.L, angle=90,length=length) > } > > CI.plot(D,SE,0.01) > > thanks, > -- > \m/ > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.