Get all leaf paths in a nested list

Get all leaf paths in a nested list

Usage

list_path(x)

Arguments

x

A nested list to traverse.

Lists are traversed recursively. Non-list objects are treated as leaves. Data frames are not traversed and are treated as leaf values.

Value

A list of character vectors.

Each element of the returned list is the path to one leaf value in x. If x has no leaves, an empty list is returned.

See also

list_get(), list_has()

Other lstrrr_core: list_delete(), list_depth(), list_get(), list_has(), list_nleaf(), list_set()

Examples

x <- list(
  a = 1,
  b = list(
    x = 1,
    y = list(i = 1, j = 2)
  )
)

res <- list_path(x)
res
#> [[1]]
#> [1] "a"
#> 
#> [[2]]
#> [1] "b" "x"
#> 
#> [[3]]
#> [1] "b" "y" "i"
#> 
#> [[4]]
#> [1] "b" "y" "j"
#> 

# The paths can be used with list_get()
lapply(res, \(path) list_get(x, path))
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 1
#> 
#> [[3]]
#> [1] 1
#> 
#> [[4]]
#> [1] 2
#> 

# Top-level leaves have paths of length 1
list_path(list(a = 1, b = 2))
#> [[1]]
#> [1] "a"
#> 
#> [[2]]
#> [1] "b"
#> 

# Unnamed elements use their position as character labels
list_path(list(10, list(20, z = 30)))
#> [[1]]
#> [1] "1"
#> 
#> [[2]]
#> [1] "2" "1"
#> 
#> [[3]]
#> [1] "2" "z"
#> 

# Data frames are treated as leaves
list_path(list(a = data.frame(x = 1:3), b = list(c = 1)))
#> [[1]]
#> [1] "a"
#> 
#> [[2]]
#> [1] "b" "c"
#>