尝试将颜色更改为灰度 ggplot2 时图例消失

Question

graph <- structure(list(Obstacle = structure(c(4L, 2L, 3L, 1L), .Label = c("Major Obstacle", 
"Minor Obstacle", "Moderate Obstacle", "No Obstacle", "Total"
), class = "factor"), `Crime = 1` = c(0.842430787355193, 0.724891824185835, 
0.692470837751856, 0.673805601317957), `Crime = 2` = c(0.157569212644807, 
0.275108175814165, 0.307529162248144, 0.326194398682043)), row.names = c(NA, 
4L), class = "data.frame")
graph <- melt(graph, id="Obstacle")

            Obstacle Crime = 1 Crime = 2
1       No Obstacle 0.8424308 0.1575692
2    Minor Obstacle 0.7248918 0.2751082
3 Moderate Obstacle 0.6924708 0.3075292
4    Major Obstacle 0.6738056 0.3261944

如果我这样做，我会得到颜色和图例。

graph %>% 
  mutate(Obstacle = fct_relevel(Obstacle, "No Obstacle", "Minor Obstacle", "Moderate Obstacle", "Major Obstacle")) %>%
  ggplot(aes(x = Obstacle, y=value, colour=variable, group = variable)) +
  scale_y_continuous(breaks = scales::pretty_breaks(n = 20)) +
  geom_line() 

我想把它变成这样的黑白，但后来线条相同，不再有传说。 我究竟做错了什么？

graph %>% 
  mutate(Obstacle = fct_relevel(Obstacle, "No Obstacle", "Minor Obstacle", "Moderate Obstacle", "Major Obstacle")) %>%
  ggplot(aes(x = Obstacle, y=value, fill=variable, group = variable)) +
  scale_y_continuous(breaks = scales::pretty_breaks(n = 20)) +
  scale_fill_grey() +
  geom_line() 

Answer 1

尝试这个：

library(dplyr)
library(ggplot2)
library(forcats)

graph %>% 
  # reshape2::melt(graph, id="Obstacle") %>% 
  mutate(Obstacle = fct_relevel(Obstacle, "No Obstacle", "Minor Obstacle", "Moderate Obstacle", "Major Obstacle")) %>%
  ggplot(aes(x = Obstacle, y=value, colour=variable, group = variable)) +
  scale_y_continuous(breaks = scales::pretty_breaks(n = 20)) +
  geom_line() 

graph %>% 
  # reshape2::melt(graph, id="Obstacle") %>% 
  mutate(Obstacle = fct_relevel(Obstacle, "No Obstacle", "Minor Obstacle", "Moderate Obstacle", "Major Obstacle")) %>%
  ggplot(aes(x = Obstacle, y=value, colour=variable, group = variable)) +
  geom_line() +  
  scale_y_continuous(breaks = scales::pretty_breaks(n = 20)) +
  scale_colour_grey()

在您的第二个ggplot ，您混合了fill和colour 。 设置：

• colour=variable在aes中而不是fill=variable
• scale_colour_grey而不是scale_fill_gray