Dear all, Is there a possibility to remove a geom from a ggplot? Background suppose I have a function which returns a ggplot object after some data re-formatting and aggregation. While this ggplot object is fine in 90% of the cases it turns out that for some cases I want to suppress one of the layers which was added to the plot.
I could look at the source code of the function and write a new one, which has an additional flag parameter, with which I could ask the function to add or not to add the geom, but this sounds a bit of overkill to me and it would be nice, if I could just remove the particular layer? An example is in order to make my point clearer: library(ggplot2) d <- data.frame(x=rep(1:10, each = 10), y = rnorm(100), grp = rep(1:10, 10)) makePlot <- function() { ggplot(d, aes(x = x, y = y)) + stat_summary(fun.data = "mean_cl_normal", color = "red") + geom_point() } (p <- makePlot()) ## Now I want to have lines instead of points, but of course the points are still there p + geom_line(aes(group = grp, color = grp)) Again, it would not be difficult to rewrite makePlot to deal with that, but for me this seems to be error prone / duplication. So ideally, I would like to do something like: p %-% geom_point() which is ambiguous of course, as there can be several point layers in the plot. Looking at str(p) I see that there is a layers slot, so I can do q <- p q$layers <- q$layers[-2] q + geom_line(aes(group = grp, color = grp)) which does actually what I want. However, is there a way to do that in a more automated way? For now I have to inspect the object and to decide which layer I want to delete, otherwise I can get something like this: makePlot2 <- function() { ggplot(d, aes(x = x, y = y)) + geom_point() + stat_summary(fun.data = "mean_cl_normal", color = "red") } q <- makePlot2() q$layers <- q$layers[-2] q + geom_line(aes(group = grp, color = grp)) which removes the error bars but not the points (as the order in layers changed). So any ideas how to proceed in this case? If there is a nice way, I could even think of overloading %-% which would fit nicely in the idea of a plot which can not only be added layer by layer, but where I also could remove certain layers. Maybe (and even probable) there is a very good idea why I should not do that at all and I would be curious to hear these things as well. For now I am yet interested to know how I can remove layers of a plot conveniently. Thanks for your help! Kind Regards, Thorn Thaler ______________________________________________ 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.