Recursively dis-embed objects in lists of lists to a single, linear list of list objects.
Usage
list_iron(
...,
name_spec = "{outer}|{inner}",
name_repair = c("minimal", "unique", "check_unique", "universal", "unique_quiet",
"universal_quiet"),
.f = identity
)Arguments
- ...
objects or list of objects.
- name_spec
If both inner and outer names are present, control how they are combined. Should be a glue specification that uses variables
innerandouter.- name_repair
One of
"minimal","unique","universal", or"check_unique". Seevctrs::vec_as_names()for the meaning of these options.- .f
function to apply to every object in the list; default function is
identity.
Details
If object is not in a list,
list_ironplaces the object in a list.Removes all empty embedded lists.
Removes empty comma-separated arguments.
Because spreadsheets tabs have no hierarchical structure, any list of data objects to prepare for presentation within a workbook must be flattened to sheets. This function is a precursor for printing listed data objects with xlr.
list_iron forces all objects in an embedded object list to become a
single-file list, and optionally conform to a function passed by the user, e.g. entibble().
list_iron acts similar to purrr::list_flatten(), but collapses all embedded
lists rather than a single layer. Also concatenates embedded-list names via parameter name_spec.
Examples
head(iris) |> list_iron()
#> $`head(iris)`
#> Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#> 1 5.1 3.5 1.4 0.2 setosa
#> 2 4.9 3.0 1.4 0.2 setosa
#> 3 4.7 3.2 1.3 0.2 setosa
#> 4 4.6 3.1 1.5 0.2 setosa
#> 5 5.0 3.6 1.4 0.2 setosa
#> 6 5.4 3.9 1.7 0.4 setosa
#>
head(iris) |> list() |> list() |> list() |> list_iron()
#> $`list(list(list(head(iris))))`
#> Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#> 1 5.1 3.5 1.4 0.2 setosa
#> 2 4.9 3.0 1.4 0.2 setosa
#> 3 4.7 3.2 1.3 0.2 setosa
#> 4 4.6 3.1 1.5 0.2 setosa
#> 5 5.0 3.6 1.4 0.2 setosa
#> 6 5.4 3.9 1.7 0.4 setosa
#>
list_iron(list(list(iris)), mtcars, .f = ~tail(., 2))
#> $`list(list(iris))`
#> Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#> 149 6.2 3.4 5.4 2.3 virginica
#> 150 5.9 3.0 5.1 1.8 virginica
#>
#> $mtcars
#> mpg cyl disp hp drat wt qsec vs am gear carb
#> Maserati Bora 15.0 8 301 335 3.54 3.57 14.6 0 1 5 8
#> Volvo 142E 21.4 4 121 109 4.11 2.78 18.6 1 1 4 2
#>
# Compare list structure to purrr::list_flatten():
a_list <- list(list(1, list(), 2, list(3)))
a_list |> str()
#> List of 1
#> $ :List of 4
#> ..$ : num 1
#> ..$ : list()
#> ..$ : num 2
#> ..$ :List of 1
#> .. ..$ : num 3
a_list |> purrr::list_flatten() |> str()
#> List of 4
#> $ : num 1
#> $ : list()
#> $ : num 2
#> $ :List of 1
#> ..$ : num 3
a_list |> list_iron() |> str()
#> List of 3
#> $ a_list|1: num 1
#> $ a_list|2: num 2
#> $ a_list|3: num 3
# Naming examples:
messy_list <- list(list(list(1:5), a = list(5:1, 'green', list('blue')), letters))
messy_list |> str()
#> List of 1
#> $ :List of 3
#> ..$ :List of 1
#> .. ..$ : int [1:5] 1 2 3 4 5
#> ..$ a:List of 3
#> .. ..$ : int [1:5] 5 4 3 2 1
#> .. ..$ : chr "green"
#> .. ..$ :List of 1
#> .. .. ..$ : chr "blue"
#> ..$ : chr [1:26] "a" "b" "c" "d" ...
messy_list |> list_iron() |> str()
#> List of 5
#> $ messy_list| : int [1:5] 1 2 3 4 5
#> $ messy_list|a|1: int [1:5] 5 4 3 2 1
#> $ messy_list|a|2: chr "green"
#> $ messy_list|a|3: chr "blue"
#> $ messy_list| : chr [1:26] "a" "b" "c" "d" ...
messy_list |> list_iron(name_repair = 'unique') |> names()
#> [1] "messy_list|...1" "messy_list|a|1" "messy_list|a|2" "messy_list|a|3"
#> [5] "messy_list|...5"
messy_list |> list_iron(name_spec = '', name_repair = 'unique') |> names()
#> [1] "...1" "...2" "...3" "...4" "...5"
messy_list |> list_iron(name_spec = '{outer}', name_repair = 'unique') |> names()
#> [1] "messy_list...1" "messy_list...2" "messy_list...3" "messy_list...4"
#> [5] "messy_list...5"