如何在ggplot中为标签添加表达式

Question

我已经能够添加基于方面的标签，但是，如何将其标签设为文本：

"Mean = 0.235" 而不仅仅是“0.235”

这是我的 ggplot，其中重要的部分是 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)

这是一张图片，显示了每个方面的标签：

Answer 1

你有（至少）两个选择。

创建合适的字符串

# 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)

在对 geom_text 的调用中使用 parse=TRUE。在这种情况下，您需要根据 ?plotmath（和 ?geom_text）

构造适当的表达式

  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 "nicer" 外观表达式。

如何在ggplot中为标签添加表达式

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