r - ggplot 在 geom_histogram 中不显示图例

Question

我有这个代码

ggplot()
+ geom_histogram(aes(x=V1, y=(..count..)/sum(..count..)), fill="red", alpha=.4, colour="red", data=coding, stat = "bin", binwidth = 30)
+ geom_histogram(aes(x=V1,y=(..count..)/sum(..count..)), fill="blue", alpha=.4, colour="blue", data=lncrna, stat = "bin", binwidth = 30)
+ coord_cartesian(xlim = c(0, 2000))
+ xlab("Size (nt)")
+ ylab("Percentage (%)")
+ geom_vline(data=cdf, aes(xintercept=rating.mean, colour=Labels), linetype="dashed", size=1)

产生一个没有图例的漂亮直方图:



在我访问的每个帖子中都有同样的问题，他们说把 color内 aes .尽管如此，这并没有给出任何传说。

我试过:

ggplot() + geom_histogram(aes(x=V1, y=(..count..)/sum(..count..),color="red", fill="red"), fill="red", alpha=.4, colour="red", data=coding, stat = "bin", binwidth = 30)
+ geom_histogram(aes(x=V1,y=(..count..)/sum(..count..), color="blue", fill="blue"), fill="blue", alpha=.4, colour="blue", data=lncrna, stat = "bin", binwidth = 30)
+ coord_cartesian(xlim = c(0, 2000))
+ xlab("Size (nt)")
+ ylab("Percentage (%)")
+ geom_vline(data=cdf, aes(xintercept=rating.mean, colour=Labels), linetype="dashed", size=1)

没有成功。

如何在图表中放置图例？

Answer 1

如果您不想将数据放在一个 data.frame 中，您可以这样做:

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"))