ggplot中为阈值线上方点添加id标签运行报错求助

• 语法缺失：geom_label_repel() 代码块末尾没有加 + 连接后续的labs()函数，导致图层链断裂，ggplot无法识别后续参数
• 全局映射不兼容子集数据：全局aes()中直接指定x = as.numeric(row.names(df.sample))，当geom_text_repel、geom_label_repel调用只有1行的离群点子集时，继承的x映射长度和子集数据长度不匹配，触发长度校验错误
• 冗余图层：同时调用geom_text_repel和geom_label_repel功能重叠，无需同时使用
• 阈值标注映射冲突：标注阈值线的geom_text继承了全局映射，容易和固定位置的参数产生冲突

library(tidyverse)    
library(ggplot2)
library(ggrepel)  
library(scales)  
library(ggthemes)  

df.sample %>%
  ggplot(aes(x = as.numeric(row.names(.)), # 用.指代管道传入的数据，避免全局变量引用问题
             y = amount, label = as.character(id))) + 
  geom_point(alpha = 0.6, position = position_jitter(w = 0.05, h = 0.0), 
             aes(colour = (amount < 3)), size = 2) +
  geom_hline(aes(yintercept = 3, linetype = "Limit"), 
             color = 'black', size = 1) +      
  # 阈值标注关闭全局映射继承，避免长度不匹配
  geom_text(inherit.aes = FALSE,
            aes(y = 3, x = 2, # 可根据实际数据量调整x位置
                label = paste("Limit = ", round(3, 3))),
            hjust = 0, vjust = 1.5) +
  # 保留单个标签图层即可，带背景的label_repel可读性更强
  geom_label_repel(data = subset(df.sample, outlier == 'TRUE'),
                   nudge_y = 0.75,
                   size = 4,
                   box.padding = 0.5,
                   point.padding = 0.5,
                   force = 100,
                   segment.size = 0.2,
                   segment.color = "grey50",
                   direction = "x") + # 补上缺失的图层连接符+
  labs(title = "Outlier Detection",
       y = "amount",
       x = "") +
  theme_few() +
  theme(legend.position = "none",
        axis.text = element_text(size = 10, face = "bold"), 
        axis.title = element_text(size = 10, face = "bold"),
        plot.title = element_text(colour = "blue", hjust = 0.5,
                                  size = 15, face = "bold"),
        strip.text = element_text(size = 10, face = "bold")) +
  scale_colour_manual(values = c("TRUE" = "green","FALSE" = "red"))

如果不需要标签带白色背景，可直接把geom_label_repel替换为geom_text_repel。

内容的提问来源于stack exchange，提问作者Sharath