当您拥有并非全部列的多个变量时，如何指定GGPLOT传奇顺序？

Question

我使用 ggplot 按不同的时间尺度（周、月、季度等）绘制相同的数据，因此，我从不同的列中提取数据。然而，当我看到我的图例时，我希望它是一个特定的顺序。

我知道如果所有分组变量都在一列中，我可以将其设置为有序因子，正如它所解释的此处，但我的数据分布在多个列中。我还尝试了此处关于重新排序多个geoms的建议，但它没有不工作。

因为我的实际数据集非常复杂，所以我复制了一个较小的版本，其中只有周和月的数据。对于最终答案，请允许它指定特定的顺序，而不仅仅是像 rev() 这样的东西，因为在我的实际数据集中，我有 6 列需要特定的顺序命令。

下面是要重现的代码 - 为此，前 3 个块构成数据集，因此只有用于绘制图的第 4 个块应该与实际解决方案相关。 R 显示顺序的默认情况是在图例中首先显示“分数 - 月份”，所以我想看看如何使其成为第二个。

library(dplyr)
library(ggplot2)
library(lubridate)

#Generates week data -- shouldn't be relevant to troubleshoot
by_week <- tibble(Week = seq(as.Date("2011-01-01"), as.Date("2012-07-01"), by="weeks"),
                Week_score = c(sample(100:200, 79)),
                Month = ymd(format(Week, "%Y-%m-01")))

#Generates month data -- shouldn't be relevant to troubleshoot                
by_month <- tibble(Month = seq(as.Date("2011-01-01"), as.Date("2012-07-01"), by="months"),
                   Month_score = c(sample(150:200, 19)))

#Joins data and removes duplications of month data for easier plotting -- shouldn't be relevant to troubleshoot  
all_time <- by_week %>%
  full_join(by_month) %>%
  mutate(helper = across(c(contains("Month")), ~paste(.))) %>% 
  mutate(across(c(contains("Month")), ~ifelse(duplicated(helper), NA, .)), .keep="unused") %>%
  mutate(Month = as.Date(Month))

#Makes plot - this is where I want the order in the legend to be different
all_time %>%
  ggplot(aes(x = Week)) +
  geom_line(aes(y= Week_score, colour = "Week_score")) +
  geom_line(data=all_time[!is.na(all_time$Month_score),], aes(y = Month_score, colour = "Month_score")) + #This line tells R just to focus on non-missing values for Month_score
  scale_colour_discrete(labels = c("Week_score" = "Score - Week", "Month_score" = "Score - Month"))

这就是当前图例的样子——我希望使用可扩展到 2 个以上选项的解决方案来切换顺序。谢谢你！

Answer 1

正如 @stefan 在评论中提到的，您应该在 scale_colour_discrete 的 limits 选项中设置标签名称。您可以自己添加更多列。您可以使用以下代码：

library(dplyr)
library(ggplot2)
library(lubridate)

#Generates week data -- shouldn't be relevant to troubleshoot
by_week <- tibble(Week = seq(as.Date("2011-01-01"), as.Date("2012-07-01"), by="weeks"),
                  Week_score = c(sample(100:200, 79)),
                  Month = ymd(format(Week, "%Y-%m-01")))

#Generates month data -- shouldn't be relevant to troubleshoot                
by_month <- tibble(Month = seq(as.Date("2011-01-01"), as.Date("2012-07-01"), by="months"),
                   Month_score = c(sample(150:200, 19)))

#Joins data and removes duplications of month data for easier plotting -- shouldn't be relevant to troubleshoot  
all_time <- by_week %>%
  full_join(by_month) %>%
  mutate(helper = across(c(contains("Month")), ~paste(.))) %>% 
  mutate(across(c(contains("Month")), ~ifelse(duplicated(helper), NA, .)), .keep="unused") %>%
  mutate(Month = as.Date(Month))

#Makes plot - this is where I want the order in the legend to be different
all_time %>%
  ggplot(aes(x = Week)) +
  geom_line(aes(y= Week_score, colour = "Week_score")) +
  geom_line(data=all_time[!is.na(all_time$Month_score),], aes(y = Month_score, colour = "Month_score")) + #This line tells R just to focus on non-missing values for Month_score
  scale_colour_discrete(labels = c("Week_score" = "Score - Week", "Month_score" = "Score - Month"), limits = c("Week_score", "Month_score"))

输出：

如您所见，标签的顺序已更改。