ggplot does not show legend in geom_histogram

Question

I have this code

ggplot()
+ geom_histogram(aes(x=V1, y=(..count..)/sum(..count..)), fill=\"red\", alpha=.4, colour=\"red\", data=coding, stat = \"bin\", binw         


        

Answer 1

If you don't want to put the data in one data.frame, you can do this:

set.seed(42)
coding <- data.frame(V1=rnorm(1000))
lncrna <- data.frame(V1=rlnorm(1000))


library(ggplot2)
ggplot() + 
  geom_histogram(aes(x=V1, y=(..count..)/sum(..count..), fill="r", colour="r"), alpha=.4, data=coding, stat = "bin") +
  geom_histogram(aes(x=V1,y=(..count..)/sum(..count..), fill="b", colour="b"), alpha=.4, data=lncrna, stat = "bin") +
  scale_colour_manual(name="group", values=c("r" = "red", "b"="blue"), labels=c("b"="blue values", "r"="red values")) +
  scale_fill_manual(name="group", values=c("r" = "red", "b"="blue"), labels=c("b"="blue values", "r"="red values"))