How to change labels (legends) in ggplot?
Solution 1
Is mat$type
a factor? If not, that will cause the error. Also, you can't use labels(...)
this way.
Since you did not provide any data, here's an example using the built-in mtcars
dataset.
ggplot(mtcars, aes(x=hp,color=factor(cyl)))+
geom_density()+
scale_color_manual(name="Cylinders",
labels=c("4 Cylinder","6 Cylinder","8- Cylinder"),
values=c("red","green","blue"))
In this example,
ggplot(mtcars, aes(x=hp,color=cyl))+...
would cause the same error that you are getting, because mtcars$cyl
is not a factor.
Solution 2
As a complement to @jlhoward's answer, scale_color_manual()
is more intended to customize the color scale (the actual colors that will be displayed).
For your case, you might rather use scale_color_discrete()
:
ggplot(mtcars, aes(x=hp,color=factor(cyl)))+
geom_density()+
scale_color_discrete(name="Cylinders",
labels=c("4 Cylinder","6 Cylinder","8- Cylinder"))
This is quicker, but it is dependant on the factor levels order, which might lead to irreproducibility. You might want to specify the breaks
argument to minimise the risk of error (and customize the order in the legend):
ggplot(mtcars, aes(x=hp,color=factor(cyl)))+
geom_density()+
scale_color_discrete(name="Cylinders",
breaks=c(8,6,4),
labels=c("8 Cylinder","6 Cylinder","4 Cylinder"))
More info on https://ggplot2-book.org/scales.html.
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Comments
-
Chen almost 2 years
My code is like below, I want to change the label of the ggplot, but R always remind me:
Error in unit(tic_pos.c, "mm") : 'x' and 'units' must have length > 0
What should I do?
ggplot(mat,aes(x=sales,col=type))+ geom_density()+labels("red_sold","blue_sold","yellow_sold")
-
Dan Chaltiel almost 5 yearsOf note, it is possible to change
name
andlabels
with keeping the defaultsvalues
by usingscale_color_discrete()
instead. -
Fabian Winkler almost 4 years@DanChaltiel Maybe you could post your comment as a regular answer, so it's easier to find?