如何将图例添加到组合 ggplot2（不同的值）

Question

我需要在我的组合 ggplot 中添加一个图例，但似乎没有成功。 数据由三个不同的值组成，其中“目标”和“非目标”在一个图中，“响应”在另一个图中。 我想在组合图的底部添加图例。 提前致谢

我当前代码的输出

A <- ggplot(placeholder) + 
  geom_line(aes(x=date, y= targeted), color='#0072b2', group= 1, size=1.25) + 
  geom_line(aes(x=date, y= non_targeted), color='#d55e00' , group= 1, size=1.25) +
  theme(axis.text.x = element_text(angle = 90)) +
  labs(y= "Y1", x = "Date") + theme_classic() +
  theme(axis.text.x = element_text(angle = 90))


A 

B <- ggplot(media_analysis) + 
  geom_line(aes(x=date, y= nuisance_reports), color='#f0e442', group= 1, size=1.25) +
  theme(axis.text.x = element_text(angle = 90)) +
  labs(y= "Y2", x = "Date") + theme_classic() +
  theme(axis.text.x = element_text(angle = 90))

B 

combined <- plot_grid(A, B, 
                      labels = c("A", "B"),
                      ncol = 2, nrow = 1)  
combined

Answer 1

最简单的是使用分面。 这需要少量的数据争论（见评论）。

suppressMessages(library(tidyverse))

set.seed(42)
foo <- cbind(data.frame(replicate(3, rnorm(30))), date = ISOdate(1,1,1:30))

# make a data frame which has all the values in one column, 
# and all the dates in another
# there needs to be a facetting variable

foo %>% 
  pivot_longer(starts_with("X")) %>%
  ## combine X1 and X2 to one category
  mutate(new_name = ifelse(grepl("X[1-2]", name), "A", "B")) %>%
  ## now facet by this new variable
  ggplot() +
  geom_line(aes(date, value, color = name)) +
  facet_wrap(~new_name) +
  ## place at bottom
  theme(legend.position = "bottom")

或将情节与拼凑而成

这将需要指南的相同名称和限制

library(patchwork)
p1 <-  
  foo %>% 
  pivot_longer(matches("X[1-2]")) %>%
  ggplot() +
  geom_line(aes(date, value, color = name)) +
  ## now define the same names for your color legend and get the same limits
  scale_color_brewer("color", limits = paste0("X", 1:3))

p2 <-  foo %>% 
  ggplot() +
  geom_line(aes(date, X3, color = "X3")) +
  scale_color_brewer("color", limits = paste0("X", 1:3))

p1 + p2 +
  ## combine the legends 
  plot_layout(guides = "collect") +
  # add tags 
  plot_annotation(tag_levels = "A") &
  ## place at bottom
  theme(legend.position = "bottom")

^{由reprex 包于 2022-06-29 创建 (v2.0.1)}