Overlay violin plots in r-CodePudding

I am trying to plot overlaying violin plots by condition within the same variable.

Var <- rnorm(100,50)
Cond <- rbinom(100, 1, 0.5)
df2 <- data.frame(Var,Cond)

ggplot(df2) 
  aes(x=factor(Cond),y=Var, colour = Cond) 
  geom_violin(alpha=0.3,position="identity") 
  coord_flip()

So, where do I specify that I want them to overlap? Preferably, I want them to become more lighter when overlapping and darker colour when not so that their differences are clear. Any clues?

CodePudding user response：

If you don't want them to have different (flipped) x-values, set x to a constant instead of x = factor(Cond). And if you want them filled in, set a fill aesthetic.

ggplot(df2) 
  aes(x=0,y=Var, colour = Cond, fill = Cond) 
  geom_violin(alpha=0.3,position="identity") 
  coord_flip()

coord_flip isn't often needed anymore--since version 3.3.0 (released in early 2020) all geoms can point in either direction. I'd recommend simplifying as below for a similar result.

df2$Cond = factor(df2$Cond)
ggplot(df2)  
  aes(y = 0, x = Var, colour = Cond, fill = Cond)  
  geom_violin(alpha = 0.3, position = "identity")