R/etl_transform.R

In nyctaxi: Accessing New York City Taxi Data

#' @import etl
#' @importFrom rlang .data
#' @export
#' @rdname etl_extract.etl_nyctaxi
#' @details transform NYC Yellow taxi trip data from raw directory to load directory
#' and/or \code{green}. The default is \code{yellow}.
#' @inheritParams get_file_path
#' @seealso \code{\link[etl]{etl_transform}}


etl_transform.etl_nyctaxi <- function(obj, years = as.numeric(format(Sys.Date(),'%Y')), 
                                    months = 1:12, 
                                    types  = "yellow", ...) {
  
  message("Transforming data from raw directory to load directory...")
  
  #create a df of file path of the files that the user wants to transform
  remote <- get_file_path(years, months, types, path = attr(obj, "raw_dir")) 
  remote_green <- remote %>% 
    filter(rlang::.data$type == "green")
  
  #create a df of file path of the files that are in the raw directory
  src <- list.files(attr(obj, "raw_dir"), "\\.csv", full.names = TRUE)
  
  #only keep the files thst the user wants to transform
  src_small <- intersect(src, remote$src)
  
  src_small_green <- intersect(src, remote_green$src)
  
  if (length(src_small) == 0) {
    message("The files you requested are not available in the raw directory.")
  } else {
    #find the load directory
    lcl <- file.path(attr(obj, "load_dir"), basename(src_small))
    lcl_green <- file.path(attr(obj, "raw_dir"), basename(src_small_green))
    
    # check that the type is green, and then do this
    if (.Platform$OS.type == "unix"){
      cmds <- paste("sed -i -e '2d'", lcl_green)
      lapply(cmds, system)
    } else {
      message("Windows system does not currently support this function...")
    }
    
    #copy the files in the raw directory and paste them to the load directory
    file.copy(from = src_small, to = lcl)
  }
  
  
  
  
  #is it caused by invisible obj?
  invisible(obj)
}