ggplot2：条形图和折线图组合对齐

Question

我想在一个图中使用条形图绘制一个变量，而使用线形图绘制另一个变量。 这是一个最小的示例：

df <- data.frame(
   Pct_F = c(40,50,60,70,80,90),
   Pct_B = c(50,60,70,80,90,95),
   Time  = c("Pre","Pre","Pre","Post","Post","Post"),
   Variable = c("Var1","Var2","Var3","Var1","Var2","Var3")
)

ggplot(df)+
   geom_bar(aes(x = Variable, y = Pct_F, fill = Time), stat="identity", width = 0.5, position = "dodge")+
   geom_line(aes(x = Variable, y=Pct_B, group = Time, colour=Time), stat="identity", size=2)+
   scale_y_continuous(limits = c(0,100))+
   coord_flip()+
   labs(title="Test Chart", x= "", y = "Percent", caption = "(Note: Bars refer to Pct_F and lines refer to Pct_B)")

这是结果图： bar and line plot

注意线条与条形边缘的对齐方式吗？如何使线条与条的中心对齐？

谢谢！

Answer 1

您可以使用position_dodge()手动添加它。另外，geom_col是您想将geom_bar与stat = "identity"一起使用的方式。

library(ggplot2)
df <- data.frame(
  Pct_F = c(40,50,60,70,80,90),
  Pct_B = c(50,60,70,80,90,95),
  Time  = c("Pre","Pre","Pre","Post","Post","Post"),
  Variable = c("Var1","Var2","Var3","Var1","Var2","Var3")
)
dodge = position_dodge(0.5)
ggplot(df)+
  geom_col(aes(x = Variable, y = Pct_F, fill = Time), width = 0.5, position = "dodge")+
  geom_line(aes(x = Variable, y=Pct_B, group = Time, colour=Time), stat="identity", size=2, position = dodge)+
  scale_y_continuous(limits = c(0,100))+
  coord_flip()+
  labs(title="Test Chart", x= "", y = "Percent", caption = "(Note: Bars refer to Pct_F and lines refer to Pct_B)")

输出：