Try this:
e <- expression(O[3], NO, NO[2]) opar <- par(mfrow = c(2,2)) for(i in 1:3) plot(1, 1, type = "b", main = bquote(.(e[[i]]) ~ Year ~ 2005)) par(opar) Also please read the last line to every post to r-help and particularly note the part about reproducible examples. x and y.were undefined. On 12/20/06, MrJ Man <[EMAIL PROTECTED]> wrote: > Greetings, > > I would like to use a data.frame with strings to feed > the expression() in the title of a plot. The way I did > this is: > > molecules > <-data.frame(name=c("o3","no","no2"),expression=c("quote(O[3])","quote(NO)","quote(NO[2])")) > > for (mol in c(5,7,9)) { > plot(x, y, type="b", > main=eval(substitute(expression(paste(mol," Year > 2005")), > > list(mol=eval(parse("",text=toString(molecules$expression[(mol-3)/2]))))))) > } > > However, this looks cumbersome and I'm sure there is a > way to do this in R that is much more simple. The > complexity of the expression above is mainly due to > the fact that the only way I could find to convert a > string read from a data.frame into a symbol was to > enclose it in "quote(symbol)" and call toString on the > result, since selecting string data from a data.frame > returns an object that is not a string (why is this > so? A data.frame with doubles returns doubles). > > What do you think? > > Thanks in advance. > > ______________________________________________ > R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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.