从使用2种不同几何图形创建的ggplot图例中删除某些值

用户名

我制作了一个ggplot图，其中的图例是由2种不同几何图形的映射组成的，如下所示：


# Create data.frame with shading info
shading <- data.frame(min = seq(from = 0.5, to = max(as.numeric(as.factor(mtcars$carb))), by = 1),
                      max = seq(from = 1.5, to = max(as.numeric(as.factor(mtcars$carb))) + 0.5, by = 1),
                      col = c(0,1))

# Plot
ggplot() +
  geom_col(data = mtcars, mapping = aes(x = factor(carb), y = mpg, fill = factor(cyl))) +
  geom_rect(data = shading,
            aes(xmin = min, xmax = max, ymin = -Inf, ymax = Inf,
                fill = factor(col)), alpha = 0.3) +
  scale_fill_manual(values = c("black", "white", "green", "blue", "red")) +
  geom_col(data = mtcars, mapping = aes(x = factor(carb), y = mpg, fill = factor(cyl)))

如何从图例中删除前两个图例项（黑色0和白色1），但将其保留在图形中？

谢谢

ravic_

您可以在scale_fill_manual()通话中明确设置休息时间-允许您说出哪些会被标记，哪些不会被标记。（我在这里保留了其余的代码）。如果您正在寻找更多信息和演练，请访问：https : //luisdva.github.io/rstats/set-the-breaks/

library(ggplot2)
shading <- data.frame(min = seq(from = 0.5, to = max(as.numeric(as.factor(mtcars$carb))), by = 1),
                      max = seq(from = 1.5, to = max(as.numeric(as.factor(mtcars$carb))) + 0.5, by = 1),
                      col = c(0,1))

# Plot
ggplot() +
  geom_col(data = mtcars, mapping = aes(x = factor(carb), y = mpg, fill = factor(cyl))) +
  geom_rect(data = shading,
            aes(xmin = min, xmax = max, ymin = -Inf, ymax = Inf,
                fill = factor(col)), alpha = 0.3) +
  scale_fill_manual(values = c("black", "white", "green", "blue", "red"),
                    # Adding breaks
                    breaks = c(4, 6, 8)) +
  geom_col(data = mtcars, mapping = aes(x = factor(carb), y = mpg, fill = factor(cyl)))