示例数据
df <- data.frame(id = rep(1:6, each = 50), x = rnorm(50*6, mean = 10, sd = 5),
y = rnorm(50*6, mean = 20, sd = 10),
z = rnorm(50*6, mean = 30, sd = 15))
ggplot(df, aes(x)) + geom_histogram() + facet_wrap(~id)
如何在不同颜色的每个id的同一个图中显示x,y,z