R语言如何改变颜色？

data<-read.csv("D:/reserchdata/a111.csv",header = T)

library("ggplot2")

p<-ggplot(data,aes(x = X))

p +geom_density(color = "black", fill = "gray")

p +geom_density(aes(color = Y))

p +geom_density(aes(fill = Y), alpha=0.4)+

geom_vline(aes(xintercept= 0.5),linetype="dashed") +

scale_x_continuous(limits= c(-1.50, 1.70),breaks=seq(-2,2,0.5))+

labs(x ="change of craving", y = "percentage of participants",title = "KDE curve of responser",fill="group")+

theme(plot.title =element_text(hjust = 0.5))+

theme_bw()+

theme(panel.border= element_blank(),panel.grid.major =element_blank(),panel.grid.minor=element_blank(),axis.line =element_line(colour = "black"))

最后出来了一个这个图形，想知道如何改这个的颜色以及图例？谢谢大佬回复！或者有没有更好的作图方法？

首先把你的数据从宽型数据转换成长型数据，然后ggplot(data, aes(x = X, fill = group)) + geom_density() + scale_fill_manual( values = c("red","blue", "black"))。注意这里的group需要是factor类型。