我需要生成很多类似格式的直方图，所以我想把具体的图代码做成一个函数，我的函数是：

DistribGraph <- function(VectorToGraph, VarName = "var", title,
                         limit_lo = 50, limit_hi = 150, bin_width = 5, tik_width = 10) {
  
  data <- data.frame(VarName = VectorToGraph)
  
  graph <- ggplot(data) +
    aes(x = VarName) +
    ggtitle(title) + 
    scale_x_continuous(breaks = seq(limit_lo, limit_hi, tik_width), 
                       limits = c(limit_lo, limit_hi)) +
    geom_histogram(aes(y = after_stat(density)),
                   binwidth = bin_width, 
                   fill = "#69b3a2", 
                   boundary = limit_lo,
                   color = "#e9ecef",  
                   alpha = 0.9) +
    theme(plot.title = element_text(size = 10, face = "bold")) +  
    stat_function(fun = dnorm, args = list(mean = mean(VectorToGraph), 
                                           sd = sd(VectorToGraph)))
  
  return(graph)
}

打个比方，

DistribGraph(mtcars$mpg, "mpg", "mpg - Histogram", 10, 35, 1, 5)

唯一的问题是x轴名称是“VarName”，而不是“mpg”。

我怀疑问题是在data.frame(VarName = VectorToGraph)或aes(x = VarName)中，因为R采用变量的名称而不是变量的内容......
问题是：如何将变量名传递为字符串，而不是包含字符串的变量？