removing part of a fill legend in ggplot

Question

I am facing a difficulty for a plot: I want to remove a part of a fill legend in a ggplot plot, while keeping the automated coloring. here is an example:

library(ggplot2)

df1 <- data.frame(x = 1:20,y1 = rnorm(20,2,0.2),y2 = sqrt(1:20))
df2 <- data.frame(x1 = c(1,5,10),x2 = c(5,10,20),color2 = as.factor(1:3))

ggplot(data=df1) +
  geom_rect(data = df2,
            aes(xmin = x1,
                xmax = x2,
                ymin = 0,
                ymax = Inf,
                fill = color2),
            color = "black",
            size = 0.3,
            alpha = 0.2)+
  geom_bar(aes(x = x,
               y= y1,
               fill = "daily"),
           stat='identity',
           width = 0.75,
           size = 0.1,
           alpha = 0.5) +
  geom_line(aes(x = x,
                y =y2,
                color = "somthing"),
            size = 1.5)

I would like to:

• keep only the daily entry of the fill legend
• keep the automated filling based on the color2 for the geom_rect
• ideally, merge the two legends (color and fill) into one

I have been playing around with scale_fill_manual and guide, but I did not come with something working. I feel that the solution could be making two independent layer and add them, but I don't know how to do that.

Does anyone know how to do ?

Answer 1

Remember you can set the breaks on any scale, so just set a single break at "daily" on your fill scale. To merge it with the color scale (if I understand your meaning) you can just give the color guide and its single break the same names as the fill guide and fill break:

ggplot(data=df1) +
  geom_rect(data = df2,
            aes(xmin = x1,
                xmax = x2,
                ymin = 0,
                ymax = Inf,
                fill = color2),
            color = "black",
            size = 0.3,
            alpha = 0.2)+
  geom_bar(aes(x = x,
               y= y1,
               fill = "daily"),
           stat='identity',
           width = 0.75,
           size = 0.1,
           alpha = 0.5) +
  geom_line(aes(x = x,
                y =y2,
                color = "somthing"),
            size = 1.5) +
  scale_fill_discrete(breaks = "daily", name = NULL) +
   scale_color_discrete(name = "labels") +
  theme(legend.margin = margin(0, 0, -10, 0))