neversaint neversaint - 3 months ago 20
R Question

How to change legend title in ggplot (density)

I have the following plot like below.
It was created with this command:

>library(ggplot2)
>df <- data.frame(cond = factor( rep(c("A","B"), each=200) ), rating = c(rnorm(200),rnorm(200, mean=.8)))
>ggplot(df, aes(x=rating, fill=cond)) + geom_density(alpha=.3)+xlab("NEW RATING TITLE")+ylab("NEW DENSITY TITLE")


Now next thing I want to do is to modify the legend title from cond into NEW LEGEND TITLE.

So what I did is to just add the following line add the end of the above code:

+labs(colour="NEW LEGEND TITLE")


But it doesn't work. What's the right way to do it?

enter image description here

Answer

This should work:

p <- ggplot(df, aes(x=rating, fill=cond)) + 
           geom_density(alpha=.3) + 
           xlab("NEW RATING TITLE") + 
           ylab("NEW DENSITY TITLE")
p <- p + guides(fill=guide_legend(title="New Legend Title"))

(or alternatively)

p + scale_fill_discrete(name = "New Legend Title")
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