Try to find path along the root directory

Try to find path under root directory even if the original path is missing; see examples.

Usage

find_path(path, root_dir, all = FALSE)

Arguments

path

file path

root_dir

top directory of the search path

all

return all possible paths, default is false

Value

The absolute path of file if exists, or NULL if missing/failed.

Details

When file is missing, find_path concatenates the root directory and path combined to find the file. For example, if path is "a/b/c/d", the function first seek for existence of "a/b/c/d". If failed, then "b/c/d", and then "~/c/d" until reaching root directory. If all=TRUE, then all files/directories found along the search path will be returned

Examples

root <- tempdir()

# ------ Case 1: basic use case -------

# Create a path in root
dir_create2(file.path(root, 'a'))

# find path even it's missing. The search path will be
# root/ins/cd/a - missing
# root/cd/a     - missing
# root/a        - exists!
find_path('ins/cd/a', root)
#> [1] "/private/var/folders/c9/jqpw9nhs7jj7vm5185nyw05h0000gn/T/Rtmph6Cicq/a"

# ------ Case 2: priority -------
# Create two paths in root
dir_create2(file.path(root, 'cc/a'))
dir_create2(file.path(root, 'a'))

# If two paths exist, return the first path found
# root/ins/cd/a - missing
# root/cd/a     - exists - returned
# root/a        - exists, but ignored
find_path('ins/cc/a', root)
#> [1] "/private/var/folders/c9/jqpw9nhs7jj7vm5185nyw05h0000gn/T/Rtmph6Cicq/cc/a"

# ------ Case 3: find all -------
# Create two paths in root
dir_create2(file.path(root, 'cc/a'))
dir_create2(file.path(root, 'a'))

# If two paths exist, return the first path found
# root/ins/cd/a - missing
# root/cd/a     - exists - returned
# root/a        - exists - returned
find_path('ins/cc/a', root, all = TRUE)
#> [1] "/private/var/folders/c9/jqpw9nhs7jj7vm5185nyw05h0000gn/T/Rtmph6Cicq/cc/a"
#> [2] "/private/var/folders/c9/jqpw9nhs7jj7vm5185nyw05h0000gn/T/Rtmph6Cicq/a"