r - 我可以在模型对象的嵌套列表上使用 rapply

Question

我可以使用rapply深入了解列表(其结构未知；可能嵌套也可能不嵌套)以提取一些信息吗？例如，我有一个模型对象列表，其中一个元素也是模型对象列表。我可以同时运行一个函数吗？

df <- data.frame(matrix(rnorm(50), nrow = 10))
names(df) <- c("X","Y1","Y2","Y3","Y4")

modlist <- list(
  m1 = lm(Y1 ~ X, data = df),
  m2 = lm(Y2 ~ X, data = df),
  m3 = list(
    m3.1 = lm(Y3 ~ X, data = df),
    m3.2 = lm(Y4 ~ X, data = df)
  )
)

从每个关系中提取截距:

getcoef <- function(x) coefficients(x)[1]

getcoef(modlist[[1]])
# works fine

rapply(modlist, getcoef, classes = "lm", how = "replace")
# returns unlisted model objects!???

Answer 1

只需重新定义您的 getcoef 函数并使用 lapply:

> getcoef <- function(x) if(inherits(x, "lm")) coefficients(x)[1] else lapply(x, getcoef)
> str(lapply(modlist, getcoef))
List of 3
 $ m1: Named num -0.143
  ..- attr(*, "names")= chr "(Intercept)"
 $ m2: Named num -0.11
  ..- attr(*, "names")= chr "(Intercept)"
 $ m3:List of 2
  ..$ m3.1: Named num 0.0743
  .. ..- attr(*, "names")= chr "(Intercept)"
  ..$ m3.2: Named num -0.577
  .. ..- attr(*, "names")= chr "(Intercept)"