Thanks for your reply. It is very helpful. I am sorry I didn't make my queston clearer. I have two concerns about this graph. One thing is denote 'sigma' and 'delta' as greek letters, usually I use 'expression'. But I don't know how to use 'expression' in the 'legend' The other thing is, the graph will also be print out with black and white. I try to use circle and squre to seperate 'delta1's curve and 'delta2's curve. So even someone read the black and white handout, they can tell which graph is which. It will be nice if there is a notation on the graph, next to a square symble, it says 'delta 1', next to a circle symble, it says'delta 2'. I wrote it on the label with phrases, looks not professional.
Thank you for any suggestons. my runable code is as follows: sigma=c( 0.00625, 0.06250, 0.12500, 0.18750, 0.25000, 0.31250, 0.37500, 0.43750, 0.50000, 0.56250) delta1=c(0.90768, 0.90489, 0.901788,0.898681, 0.8955, 0.89557, 0.892474,0.88936, 0.886262, 0.179959) delta2=c(0.90830, 0.9110998, 0.914203, 0.917308, 0.920412, 0.923517, 0.926623, 1.71524, 1.7153, 1.7154) plot(sigma, delta1, ylim=range(-0.5, 2), xlab='sigma', ylab='delta1--square delta2--circle', pch=22, type='o') par(new=TRUE) plot(sigma, delta2, ylim=range(-0.5, 2), xlab='sigma', ylab='delta1--square delta2--circle', col='red', axes=FALSE, type='o') -- View this message in context: http://old.nabble.com/symbol-in-the-plot-tp26422303p26442986.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
