R GGPLOT：添加具有不同类别数量的观测数量的标签

发布于01月02日

我如何不仅添加一个带有观测数量的标签(这里已经很好地描述了这一点)，而且还添加了不同类别的数量，例如: 在下面的情节中，每一方面都是"10 obervations for 8 models from 3 manufacturers"？

ggplot(mpg, aes(y=cty)) + 
  geom_boxplot() +
  facet_grid(cols=vars(class))

(mpg数据集的前三行如下所示:)

> head(mpg)
# A tibble: 6 × 11
  manufacturer model displ  year   cyl trans      drv     cty   hwy fl    class  
  <chr>        <chr> <dbl> <int> <int> <chr>      <chr> <int> <int> <chr> <chr>  
1 audi         a4      1.8  1999     4 auto(l5)   f        18    29 p     compact
2 audi         a4      1.8  1999     4 manual(m5) f        21    29 p     compact
3 audi         a4      2    2008     4 manual(m6) f        20    31 p     compact

推荐答案

library(ggplot2)
library(dplyr)

# Calculate summary statistics for each facet
 mpg_summary <- mpg %>%
  group_by(class) %>%
  summarize(
    n_obs = n(),
    n_models = n_distinct(model),
    n_manufacturers = n_distinct(manufacturer)
  ) %>%
  mutate(
    label = paste0(
      n_obs,
      " observation",
      ifelse(n_obs != 1, "s", ""),  # Pluralize "observation" if more than 1
      " for ",
      n_models,
      " model",
      ifelse(n_models != 1, "s", ""),  # Pluralize "model" if more than 1
      " from ",
      n_manufacturers,
      " manufacturer",
      ifelse(n_manufacturers != 1, "s", "")  # Pluralize "manufacturer" if more than 1
    )
  )


# Create the plot with facets and labels
ggplot(mpg, aes(y = cty)) +
  geom_boxplot() +
  facet_grid(cols = vars(class)) +
  geom_text(data = mpg_summary, aes(x = Inf, y = Inf, label = label), hjust = 1, vjust = 1, size = 3) +
  theme(strip.text.x = element_blank())  # Remove facet labels

解释按"类别"分组并计算观测值、独特模型和制造商. 创建组合这些统计信息的标签字符串.

在"CLASS"上，将GGPLOT与geom_boxlot和facet_grid一起使用.

利用geom_text显示自定义标签. 将标签放置在右上角，调整对齐和大小. 通过使用主题(strip.ext.x=Element_Blank())删除刻面标签来删除多余的标签.