R - ggplot lines and columns-CodePudding

I'm trying to plot a chart that one series is a column and the other is a line with points. When I plot the data using the code below, it plots the way I want. However, there is no legend in the chart. Is there a way to force the legend to appear?

Adding the show.legend = T and the group = xxx makes no difference.

data <- data.frame(
  A = c(1, 2, 3),
  B = c(1, 2, 3),
  C = c(2, 3, 4)
)

ggplot(data, aes(x = A))  
  geom_line(aes(y = C))  
  geom_point(aes(y = C))  
  geom_col(aes(y = B))

CodePudding user response：

I was able to find a solution that is not very elegant, but works for my case.

data.2 <- data.frame(
  A = c(1, 2, 3, 1, 2, 3),
  D = c('B', 'B', 'B', 'C', 'C', 'C'),
  B = c(1, 2, 3, NA, NA, NA),
  C = c(NA, NA, NA, 2, 3, 4)
)

data.2 %>% 
  ggplot(aes(x = A, y = C, col = D, fill = D))  
  geom_line()  
  geom_point()  
  geom_col(aes(y = B))  
  scale_color_manual(values = c('black', 'red'), breaks = c('B', 'C'))  
  scale_fill_manual(values = c('grey', 'transparent'), breaks = c('B', 'C'))

CodePudding user response：

You can keep the same data structure, but it is still awkward, since ggplot doesn't really "want" you to do this (map aesthetics to things that aren't really "real" aesthetics);

ggplot(data = data,aes(x = A))   
  geom_line(aes(y = C,color = "C"))   
  geom_col(aes(y = B,color = "B",fill = "B"),fill = "blue")   
  scale_color_manual(values = c("C" = "red","B" = "blue"))  
  scale_fill_manual(values = c("C" = "red","B" = "blue"))  
  guides(color = guide_legend(override.aes = list(fill = "white")))

What you're trying to accomplish here falls more closely under what ggplot would consider "annotation", i.e. you have two very disparate elements (a line and some bars) and I would typically add annotations in the graph labelling them.