对于 R ggplot 图表，如何让图例标签成为变量的值？

Question

下面的代码制作了一个图表。有蓝色条，顶部有一条灰色线。目前，图例显示条形图为“当前月份”，但我想使用名为 reportYM1 的变量的值。我尝试输入不带引号的 reportYM1，但它显示为 reportYM1，而不是变量的值。由于某种原因，条形的颜色也变成了灰色而不是蓝色。

我错过了什么？

    library(knitr)
library(markdown)
library(rmarkdown)
library(dplyr)
library(tidyr)
library(reshape2)
library(kableExtra)
library(shadowtext)
library(ggplot2)
library(RODBC)
library(lubridate)
library(formattable)
library(scales)

reportMonth = "2024-05-01"
reportMonth <- as.character(reportMonth[1,1])   
reportYM1 = format(date(reportMonth), "%b %Y")

combinedDataA <- data.frame(category.x=c('HM_Admit_1_Percentage','HM_Admit_1_Percentage','HM_Admit_1_Percentage'),
                             valueP=c(0,0.0667,0.9333),
                             label=c('99221','99222','99223'),
                             category.y=c('HM_ytdAdmit_1_Percentage','HM_ytdAdmit_1_Percentage','HM_ytdAdmit_1_Percentage'),
                             valueH=c(0,0.1162791,0.8837209))


# Plotting
ggplot(data = combinedDataA, aes(x = label)) +
  geom_bar(aes(y = valueP * 100, fill = "Current Month"), stat = "identity") +
  geom_line(aes(y = valueH * 100, group = 1, color = "YTD"), size = 1) +
  geom_point(aes(y = valueH * 100, color = "YTD"), size = 3) +
  geom_shadowtext(aes(y = 0, label = scales::percent(valueP)), vjust = -0.5, color = "white", size = 3.5, bg.colour = "black", bg.r = 0.2) +  # White text at the bottom of the bar
  scale_y_continuous(
    labels = scales::percent_format(scale = 1), 
    limits = c(0, 110), 
    expand = c(0, 0)  
  ) +
  scale_fill_manual(values = c("Current Month" = "#0060a9"), guide = guide_legend(title = NULL)) +
  scale_color_manual(values = c("YTD" = "#bdbdb1"), guide = guide_legend(title = NULL)) +
  labs(x = NULL, y = NULL, title = NULL, subtitle = NULL) +
  theme_minimal() +
  theme(legend.position = "bottom",
        axis.text.x = element_text(angle = 0, hjust = 0.5),
        axis.title.y = element_blank(),
        axis.title.y.right = element_blank())  

Answer 1

我没有

shadowtext

包，我相信它与你的问题无关，所以我不打算安装它。 这是一个基于

mtcars

数据集的 MRE，它允许您使用数据框中某一列的值来定义填充标签。 然而，这不是一种有效的做事方式，我不会推荐它。 相反，我要么编写一个自定义函数来允许您指定图例名称，要么提供一个（一行）控制数据集来执行相同的操作。

mtcars1 <- mtcars %>% 
  mutate(
    gear_fact = as_factor(gear),
    my_label = "A custom label"
  ) 

mtcars1 %>% 
  ggplot() +
    geom_bar(aes(y = cyl, fill = gear_fact)) +
    scale_fill_discrete(name = mtcars1$my_label)