如何使用两条单​​独的数据集行将ggplot图例添加到散点图

Question

当出现2条不同的行时，我不知道如何向此散点图添加图例。我已经尝试了不同类型的解决方案（例如添加scale_colour_manual），但是它不起作用。

这是代码。它可以正确生成图形，但不会显示图例。

months <- c("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December") 
num_17 <- c(NA, 12, 20, 25, 13, 22, 6, 55, 7, 44, 14, 11)
num_18 <- c(33, 21, 45, 31, 27, 42, 16, 38, 22, 19, 39, 9)
time_df <- data.frame("Months" = months, "Submissions 2017" = num_17, "Submissions 2018" = num_18)

two_colors <- c("lightblue", "orange")

time_df$Months <- factor(time_df$Months, levels=c("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"))

ggplot(time_df, aes(x = Months, color = Months, group = 1)) + 
  geom_line(y = num_17, size = 2, colour = "lightblue") + 
  geom_line(y = num_18, size = 2, colour = "orange") +
  geom_point(aes(y = num_17), size = 3, color = "blue") + 
  geom_point(aes(y = num_18), size = 3, color = "red") + 
  xlab("2017 and 2018") + ylab("Number Submissions") +
  ggtitle("Submissions By Month (2017 and 2018)") + theme_bw()+
  scale_colour_manual(name="Legend", values = c(num_17 = "2017", num_18 = "2018"))+
  theme(axis.text = element_text(size = 15), 
    axis.title.y = element_text(size = 20, margin = margin(r = 25)),
    axis.title.x = element_text(size = 20, vjust = -7),
    plot.title = element_text(size = 22, face = "bold"),
    plot.margin = unit(c(1,1,1,1), "cm"))

我只想要一个标记每个组的图例。预先感谢。

Answer 1

这应该做您想要的：

 ggplot(time_df, aes(x = Months, group = 1)) + 
   geom_line(aes(y = Submissions.2017, color="2017"), size=2) +
   geom_line(aes(y = Submissions.2018, color="2018"), size=2) +
   geom_point(aes(y = Submissions.2017), size = 3, color="blue") + 
   geom_point(aes(y = Submissions.2018), size = 3, color="red") + 
   xlab("2017 and 2018") + 
   ylab("Number Submissions") +
   ggtitle("Submissions By Month (2017 and 2018)") + 
   scale_colour_manual(values = c("lightblue", "orange")) +
   theme_bw()+
   theme(axis.text = element_text(size = 15), 
         axis.title.y = element_text(size = 20, margin = margin(r = 25)),
         axis.title.x = element_text(size = 20, vjust = -7),
         plot.title = element_text(size = 22, face = "bold"),
         plot.margin = unit(c(1,1,1,1), "cm"))