如何在ggplot中修改过长的因子水平名称并使其在图表中生效？

你当前的问题在于直接修改了整个数据框的levels，但data.frame对象本身没有levels属性，你的修改根本没作用到目标列Coding_Exp_Words上，所以绘图时还是显示原标签。

两种正确的修改方式 #

方式一：直接修改目标列的因子水平 #

针对Coding_Exp_Words列单独修改，注意原因子值在前，新标签在后，顺序要和原列的因子水平对应：

# 给Coding_Exp_Words列设置新的因子标签
levels(class_survey$Coding_Exp_Words) <- c(
  "None" = "None.",
  "Very_Little" = "Very little. I've just dipped my toe in.",
  "Bit" = "A bit. I've used coding in a limited capacity, such as for a small",
  "Some" = "Some. I've had to write code for one or two classes and am co",
  "Good_Deal" = "A good deal. I have several years of experience writing code."
)

方式二：用forcats包的fct_recode（更直观） #

tidyverse生态的forcats包提供了更清晰的因子重命名函数，新标签在前，原标签在后，无需担心顺序问题：

library(forcats)
class_survey$Coding_Exp_Words <- fct_recode(class_survey$Coding_Exp_Words,
  None = "None.",
  Very_Little = "Very little. I've just dipped my toe in.",
  Bit = "A bit. I've used coding in a limited capacity, such as for a small",
  Some = "Some. I've had to write code for one or two classes and am co",
  Good_Deal = "A good deal. I have several years of experience writing code."
)

绘图优化（可选） #

如果想让标签更美观（比如把下划线换成空格），可以在ggplot中用scale_x_discrete再次调整显示文本：

ggplot(class_survey, aes(x = Coding_Exp_Words, y = Coding_Exp_Scale)) + 
  geom_jitter() +
  scale_x_discrete(labels = c(
    "None" = "None",
    "Very_Little" = "Very Little",
    "Bit" = "A Bit",
    "Some" = "Some",
    "Good_Deal" = "Good Deal"
  ))

内容的提问来源于stack exchange，提问作者이우진