如何在ggplot中添加表达式到标签

Question

我已经能够添加基于方面的标签，但是，如何将其标记为文本：

“平均值= 0.235”而不是“0.235”

这是我的ggplot，其中重要部分是geom_text：

ggplot(data = filter(season_melt,(HOUSEHOLD_ID_ANONYMISED %in% c(37218002754,37218032412, 38443537620))), aes(factor(HOUSEHOLD_ID_ANONYMISED), value)) + 
geom_boxplot(aes(fill = factor(HOUSEHOLD_ID_ANONYMISED))) + 
facet_wrap(~Season) + 
theme(text = element_text(size=40), legend.position = "none") + 
xlab("Household ID") + 
ylab("Usage") + 
geom_hline(data = mean_season, aes(yintercept = Mean), size = 1, colour = "blue", linetype = "dashed") + 
geom_text(data = mean_season, aes(0,Mean,label = round(Mean,3),  vjust = -1, hjust = -0.1), color = "blue", size = 11)

这是一张显示每个方面标签的图片：

Answer 1

你有（至少）两个选择。

1. 创建适当的字符串

   # Something like
   geom_text(data = mean_season, 
          aes(0, Mean, label = sprintf('Mean = %0.3f', Mean),
              vjust = -1, hjust = -0.1),
          color = "blue", size = 11)
   # or
         geom_text(data = mean_season, 
          aes(0, Mean, label = paste('Mean = ',round(Mean, 3)),
              vjust = -1, hjust = -0.1),
          color = "blue", size = 11)
   

2. 在parse=TRUE的通话中使用geom_text。在这种情况下，您需要根据?plotmath（和?geom_text）构建适当的表达式

     geom_text(data = mean_season, parse = TRUE
          aes(0, Mean, label = paste('Mean ==',round(Mean, 3)),
              vjust = -1, hjust = -0.1),
          color = "blue", size = 11)
   

选项2将在可视化时创建“更好”的表情。