R-使用数据框部分展平嵌套列表

Question

我有一个具有以下结构的列表：

$ List (length 13) ; 13 Types
$ --- Lists (Length 4) ; Each have 4 subsets of the same original data
$ ------- Dataframes 1, 2, 3, and 4 ; for each of 13 types

我想要

$ List (length 52) ; 52 Versions (Type_Subset)
$ --- Dataframes 1, 2, 3, ... 52 ; As separate elements in list

如何使用下面的mtcars示例来做到这一点？

df <- list(Blue = list(mtcars[1:3,], mtcars[4:6,], mtcars[7:9,]), 
     Red = list(mtcars[10:12,], mtcars[13:15,], mtcars[16:18,]), 
     Green = list(mtcars[18:20,], mtcars[21:23,], mtcars[24:26,]))

  # Need function on df ...
  # new_df <- SingleNestLevel(df)

# Which yields: 

    list(Blue1 = mtcars[1:3,], 
         Blue2 = mtcars[4:6,], 
         Blue3 = mtcars[7:9,], 
         Red1 = mtcars[10:12,], 
         Red2 = mtcars[13:15,], 
         Red3 = mtcars[16:18,], 
         Green1 = mtcars[18:20,], 
         Green2 = mtcars[21:23,], 
         Green3 = mtcars[24:26,])

注意：我研究了类似this one之类的问题，但我想转换为一个嵌套级别，而不是完全扁平化我的结构。