如何将函数内的参数传递给 ggplot stat_summary 函数

Question

我正在尝试在函数内创建一个多面箱形图，以对患者数据进行暴露反应分析。该图按类别划分，y 轴为曝光度，x 轴为分类响应。我还想用观察数来注释该图。

一些数据：

set.seed(100)
dummy_data = data.frame(id = rep(1:50, each = 3),
                        expo = rnorm(50*3, mean = 50000, sd = 10000),
                        cat = rep(c("cat1", "cat2", "cat3"), times = 3, length.out = 50*3),
                        resp = sample(0:3, 50*3, replace = T))
outliers = data.frame(id = rep(51:60, each = 3),
                      expo = rnorm(10*3, mean = 300000, sd = 100000),
                      cat = rep(c("cat1", "cat2", "cat3"), times = 3, length.out = 10*3),
                      resp = 0)
dummy_data = rbind(dummy_data, outliers)

这是迄今为止我的代码：

boxplot_cat_er = function(data, exposure, response, cat, title = NULL, xlab = NULL, ylab = NULL) {
  give.n <- function(x){
    return(c(y = max(eval(substitute(exposure), data), na.rm = T), label = length(x)))
    # experiment with the multiplier to find the perfect position
  }
  
  ggplot(data=data, 
         aes(x = as.factor(as.character({{response}})) , y = {{exposure}}))+ 
    geom_boxplot(outlier.shape = NA) + 
    geom_jitter(width = 0.25) + 
    stat_summary(fun.data = give.n, geom = "text", color = "blue", fun.y = median, size=6) +
    xlab(xlab)+ 
    ylab(ylab)+
    ggtitle(title) +
    theme_bw() +
    theme(axis.text.x=element_text(size=15),axis.text.y=element_text(size=15),
          axis.title.y=element_text(size=15),axis.title.x=element_text(size=15),
          legend.text=element_text(size=rel(1.2)), legend.title = element_text(size = rel(1.5)),
          plot.title = element_text(size = 20)) +
    facet_grid(as.formula(paste("~", paste(substitute(cat)))), scales = "free", space = "free") +
    theme(strip.text.x = element_text(size = 15)) +
    theme(plot.title = element_text(hjust = 0.5, vjust = 1))
}

我希望它看起来像这样：

除了蓝色注释之外，一切正常。问题似乎在于我的自定义

give.n

函数被传递给

stat_summary

函数。当我运行

boxplot_cat_er(dummy_data, expo, resp, cat)

时，我得到的图没有注释，并且出现以下错误：

评估仍然在 R 中暗示我。我做错了什么？

Answer 1

问题是

expo

是您传递给绘图函数的数据集

data

的一列。为了说明这一点，您可以使用

max(data[[deparse(substitute(exposure))]], na.rm = TRUE)

计算数据中

expo

的总体最大值。在下面的代码中，我还在调用

stat_summary

之外计算一次最大值，并将其存储在变量

max_y

中。

在您的情况下，您还可以考虑使用

geom_text

和

stat="count"

:

geom_text(
      aes(label = after_stat(count), y = after_stat(max_y)),
      stat = "count", color = "blue", size = 6
    ) +

library(ggplot2)

boxplot_cat_er <- function(data, exposure, response, cat, title = NULL, xlab = NULL, ylab = NULL) {
  max_y <- max(data[[deparse(substitute(exposure))]], na.rm = TRUE)

  give.n <- function(x) {
    c(y = max_y, label = length(x))
  }

  ggplot(
    data = data,
    aes(x = as.factor(as.character({{ response }})), y = {{ exposure }})
  ) +
    geom_boxplot(outlier.shape = NA) +
    geom_jitter(width = 0.25) +
    stat_summary(
      fun.data = give.n, geom = "text",
      color = "blue", size = 6
    ) +
    facet_grid(cols = vars(cat), scales = "free", space = "free") +
    labs(x = xlab, y = ylab, title = title) +
    theme_bw() +
    theme(
      axis.text.x = element_text(size = 15), axis.text.y = element_text(size = 15),
      axis.title.y = element_text(size = 15), axis.title.x = element_text(size = 15),
      legend.text = element_text(size = rel(1.2)), legend.title = element_text(size = rel(1.5)),
      plot.title = element_text(size = 20, hjust = 0.5, vjust = 1),
      strip.text.x = element_text(size = 15)
    )
}

boxplot_cat_er(dummy_data, expo, resp, cat)