read.dir: Read files form a directory by a given function
In Lightbridge-AI/lbr: Data wrangling and analysis

Description Usage Arguments Value Examples

Read multiple files from a directory (folder) using reading engine supply by a function.

read.dir(
  fun,
  path = ".",
  pattern = "\\.csv$",
  ...,
  invert = F,
  ignore.case = F,
  perl = F,
  fixed = F,
  all.files = F,
  recursive = F,
  no.. = F,
  snake_case = F
)

`fun`	A function to read files from a directory. First argument of the function must be file path. Example : `utils::read.csv`, `readr::read_csv`, `rio::import`, `readxl::read_excel`, `base::readRDS`
`path`	Character: Path to desired directory which contain file, default is "." working directory. (passed to `base::list.files`)
`pattern`	Character: Specify regular expression to match file extension and file names. (passed to `grep()`) . Default is to read .csv file "\.csv$". Please select according to `fun`; Example, use `\\.xlsx$` to read from excel file.
`...`	Argument to pass to `fun`
`invert`	Logical: If `TRUE` read from file that file names do not match `pattern`.(passed to `grep()`)
`ignore.case`	If FALSE, the regular expression matching is case sensitive and if `TRUE`, case is ignored during matching.(passed to `grep()`)
`perl`	Logical: Should Perl-compatible regexps be used? (passed to `grep()`)
`fixed`	Logical: If `TRUE`, pattern is a string to be matched as is. Overrides all conflicting arguments.
`all.files`	If `TRUE` hidden files are also returned. (passed to `base::list.files`)
`recursive`	If `TRUE` read recursively in sub-directory.(passed to `base::list.files`)
`no..`	logical. Should both "." and ".." be excluded also from non-recursive listings? (passed to `base::list.files`)
`snake_case`	If `TRUE`: Convert names to snake_case_format. (require `snakecase` package)

A list of object returned by fun

# Not run
if(FALSE){

 # Read .csv file form working directory (default) using `utils::read.csv`.
 ## file names are set to each elements of the output.

   read.dir(utils::read.csv) # default `pattern` is "\.csv$"

 # Read .xlsx file from a directory using `readxl::read_excel`.
 ## Must specify regular expression to match file extension.

   read.dir(readxl::read_excel, path = "path/to/dir" ,pattern = "\\.xlsx$")

 # Read .rds file ; To also read form sub-directory set `recursive = TRUE` .

   read.dir(readRDS, pattern = "\\.rds$", path = "path/to/dir" ,recursive = TRUE)

 # Read files using multiple engine from multiple path and multiple file extension.

   params <- list(fun = c(read_csv, readxl::read_excel),
                path = c("path/to/dir_1", "path/to/dir_2"),
                pattern = c("\\.csv$", "\\.xlsx$"))

   purrr::pmap(params, read.dir)

   # or using base R

   ls <- vector("list", 2)

   for(i in seq_along(params[[1]])){

     ls[[i]]  <- read.dir(fun = params[[1]][[i]],  path = params[[2]][[i]],
                          pattern = params[[3]][[i]])
   }
}