Help export a single file by reducing a list of dataframes to a single one.

This function wraps purrr::reduce() and dplyr::full_join() to reduce all or some dataframes in a list into a single dataframe.

list_df(lst, df_names = NULL, by = NULL)

Arguments

lst	A list of dataframes.
df_names	Names of the list elements to join. NULL defaults to use all list elements.
by	A character vector of variables to join by. If NULL, the default, *_join() will do a natural join, using all variables with common names across the two tables. To join by different variables on x and y use a named vector. For example, by = c("a" = "b") will match x.a to y.b. Passed to dplyr::full_join()

Value

A dataframe.

See also

purrr::reduce() and dplyr::full_join().

Other general functions to export data: list_csv

Examples

dfs <- list(
  a = data.frame(x = 1),
  b = data.frame(x = 2, y = 2),
  c = data.frame(x = 1, z = 3)
)

list_df(dfs)
#>   x  y  z
#> 1 1 NA  3
#> 2 2  2 NA

list_df(dfs, df_names = c("a", "c"))
#>   x z
#> 1 1 3

list_df(dfs, df_names = c("b", "c"))
#>   x  y  z
#> 1 2  2 NA
#> 2 1 NA  3

# Use argument `by` if dataframes have no matching variable,
list_df(
  list(data.frame(x = 1), data.frame(z = 2)),
  by = c("x" = "z")
)
#>   x
#> 1 1
#> 2 2