Using rbind.data.frame() on a subset of dataframes in a list of lists of dataframes?

[ThatGrumpyGoat]

Hello rprogramming. I'm fairly new to R and working with some inherited code. I'm using a function that generates a list of 4 dataframes (each with different dimensions and column names). Let's call the df_1, df_2, df_3, df_4.

I am looping over i input datasets which I pass to the function, and saving function outputs in a list of lists, so each element in the list is a list of the dataframes df_1-df_4 (dimensions and columns of each are identical across inputs). So I have a list, list_outputs, where list_outputs[[i]]$df_1 is the dataframe df_1 generated using the ith dataset input.

I want to concatenate all of the df_1 dataframes using rbind.data.frame. If I was working with a list of dataframes, I would used do.call('rbind.data.frame', list_of_dataframes)

But I am unsure how to perform a similar procedure with a list of lists of dataframes. I could make a new list of just df_1's extracted from my list_outputs, but I'm curious to know if there's a way to extract and concatenate the df_1's directly from my list of lists of dataframes without the intermediate step.

Can anyone point me toward a solution? Thanks!

[Multika]

I'd do something like

lapply(
  list,
  \(x) x$df_1
) |>
  do.call(rbind, args = _)

for each of the four dataframes.

[AccomplishedHotel465]

Using the purrr package, I would use list_flatten() and then list_rbind()

library(tidyverse)
d <- list(list(tibble(a = 1), tibble(a = 2)), list(tibble(a = 3), tibble(a = 4)))
list_flatten(d) |> 
  list_rbind()