Rename files using purrr+stringr+fs

rename-files.R

# These two functions address a common problem in my work - files named "monthYYYY.CSV.html" - 
# e.g. "August2018.CSV.html". The prep_dir() function creates a vector of filenames in a given directory
# and then iterates over each using purrr::map(). The map() function calls our second function, edit_filename().
# For each time it is called, edit_filename() uses the magic of stringr and fs (okay, it isn't really magic)
# to rename the file appropriately.

# dependencies:
# install.packages(c("fs", "magrittr", "purrr", "stringr"))

# include in script:
library(magrittr) 

# iterate over filenames in directory
prep_dir <- function(path){
  
  # create vector of filenames
  files <- list.files(path)
  
  # iterate over each filename, renaming it and coverting to lowercase
  files %>%
    split(files) %>%
    purrr::map(~edit_filename(path = path, file = .x))
  
  # create vector of new filenames
  newFiles <- list.files(path)
  
  # create output
  out <- list(
    original = files,
    new = newFiles
  )
  
  # return output
  return(out)
  
}

# edit an individual filename
edit_filename <- function(path, file){
  
  # only edit files that end with .html
  if (stringr::str_detect(file, pattern = ".html$") == TRUE){
    
    # construct a new file name that is all lower case, removes .html from end
    newFile <- tolower(stringr::str_replace(file, pattern = ".html$", replacement = ""))
    
    # create new file paths, adding a forward slash between path and filename if necessary
    if (stringr::str_detect(path, pattern = "/$") == FALSE){
      
      filePath <- stringr::str_c(path, "/", file)
      newPath <- stringr::str_c(path, "/", newFile)
      
    } else {
      
      filePath <- stringr::str_c(path, file)
      newPath <- stringr::str_c(path, newFile)
      
    }
    
    # rename file
    fs::file_move(filePath, newPath)
    
  }
  
}