purrr：：map 会改变对象类型吗

这些差异很大程度上归结于环境的差异.例如，这些列表的第三个元素(即mtcars_formula和is_identical_1)是公式mpg~cyl(事实上mtcars_formula[[3]] == is_identical_1[[3]]将返回TRUE).但是，您将看到这些元素与不同的环境相关联.

> mtcars_formula[[3]] == is_identical_1[[3]]
[1] TRUE
> environment(mtcars_formula[[3]])
<environment: 0x560a2490ef40>
> environment(is_identical_1[[3]])
<environment: 0x560a2554d810>

您是否认为这些差异"微不足道"取决于您的用例，但您可以这样判断差异:

differences =list()
for(i in 1:length(mtcars_formula)) {
  if(!identical(mtcars_formula[[i]], is_identical_1[[i]])) {
    differences[[names(mtcars_formula)[i]]] = list(mtcars_formula[[i]], is_identical_1[[i]])
  }
}

一个确实不同的元素是报告的call(第四个元素)

> mtcars_formula[[4]] == is_identical_1[[4]]
[1] FALSE
> c(mtcars_formula[[4]], is_identical_1[[4]])
[[1]]
feols(fml = formula, data = mtcars, cluster = "gear")

[[2]]
feols(fml = formula, data = mtcars, cluster = .)

这可能与您在上面的 comments 中报告的错误有关，与fwildclusterboot::boottest()有关.注意，来自使用map()创建的对象的调用表示cluster=.，而不是'cluster="gear".

解决这个问题的一种方法是这样做:

mtcars_list_map <- map(list("gear", "gear"), function(x) {
  # create the model
  model = feols(formula, cluster = x, data = mtcars)
  # manipulate the call object
  model$call$cluster=x
  # return the model
  model
})