stat_summary：将单个观测值纳入汇总函数

Question

我想在stat_summary中“强制”一个聚合函数来计算单个观测值的输出值：

set.seed(1)
value <- c(rep(1:6, each = 3), 7:8)
rel_freq <- sample(x = seq(0, 1, 0.1), size = length(value), replace = TRUE) 
example_df <-  data.frame(value, rel_freq) 

require(ggplot2)  
ggplot() + 
  stat_summary(data = example_df,
               mapping = aes(x = as.character(value), y = rel_freq),
               fun.data = mean_se) 

# Warning message: Removed 2 rows containing missing values (geom_pointrange)

现在在这里发生的事件（IMO）是ggplot删除了观测值7和8，因为stat_summary中的聚合功能不适用于单个观测值吗？但是有办法在这里强制输出吗？

Answer 1

您可以编写自己的扩展mean_se的小函数，以处理x的长度等于1的情况。

mean_se_tjebo <- function (x, mult = 1) {
  x <- stats::na.omit(x)
  se <- mult * sqrt(stats::var(x)/length(x))
  mean <- mean(x)
  if(length(x) != 1) {
    data.frame(y = mean, ymin = mean - se, ymax = mean + se)
  } else {
    data.frame(y = mean, ymin = mean, ymax = mean)
  }
}

现在情节如下所示

ggplot() + 
  stat_summary(data = example_df,
               mapping = aes(x = as.character(value), y = rel_freq),
               fun.data = mean_se_tjebo)