在geom_bar上解析离散轴值中的上标 [英] Parse superscript in discrete axis values on geom_bar

问题描述

我试图在一些x轴值上添加上标，以便连接到位于页面底部的脚注.简单的解决方法只是将星号而不是^a，但这不适用于我的目的.

I'm trying to add a superscript to some x-axis values in order to connect to a footnote that'll be at the bottom of the page. The easy workaround would just be an asterisk instead of ^a but that won't work for my purposes.

我做了很多搜索，尽管有很多关于轴标签上标的文章，但我找不到关于轴值上标的任何文章.他们中的大多数人似乎都在中间加了gg + labs(x = expression("blah^a")).

I did a lot of searching and while there's plenty of posts about superscripts in axis labels, I couldn't find any about superscripts in axis values. Most of them appeared to centera round adding a gg + labs(x = expression("blah^a")).

我确实找到了这篇有关解析内部上标的帖子geom_text()，但对于geom_bar()来说似乎不起作用.

I did find this post about parsing superscripts inside a geom_text() but it appears the same doesn't work for a geom_bar().

以下是一些测试数据:

library(ggplot2)

dat <- data.frame(x = c("alpha", "bravo^a"),
                  y = c(10, 8))

ggplot(data = dat) +
  geom_bar(aes(x = x, 
               y = y),
           stat = "identity")

推荐答案

您只需要parse scale_x_discrete

添加geom_text示例

library(ggplot2)

dat <- data.frame(x = c("alpha", "bravo^a"),
                  y = c(10, 8))

ggplot(data = dat) +
  geom_bar(aes(x = x, 
               y = y),
           stat = "identity") +
  scale_x_discrete(labels = parse(text = levels(dat$x))) +
  geom_text(aes(x = x, y = y,
                label = x), 
            parse = TRUE, 
            nudge_y = 1,
            size = 5) +
  theme_minimal(base_size = 14)

由 reprex软件包(v0.2.0.9000)创建.

Created on 2018-08-27 by the reprex package (v0.2.0.9000).

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