R/collectData.R

In hyfo: Hydrology and Climate Forecasting

#' Collect data from different csv files.
#' 
#' @param folderName A string showing the path of the folder holding different csv files.
#' @param fileType A string showing the file type, e.g. "txt", "csv", "excel".
#' @param range A vector containing startRow, endRow, startColumn, endColumn, e.g., 
#' c(2,15,2,3)
#' @param sheetIndex A number showing the sheetIndex in the excel file, if fileType is excel,
#' sheetIndex has to be provided, default is 1.
#' @return The collected data from different files in the folder.
#' @examples 
#' 
#' #use internal data as an example.
#' folder <- file.path(path.package("hyfo"), 'extdata')
#' # file may vary with different environment, it if doesn't work, use local way to get
#' # folder path.
#' 
#' a <- collectData(folder, fileType = 'csv', range = c(10, 20, 1,2))
#' 
#' # More examples can be found in the user manual on https://yuanchao-xu.github.io/hyfo/
#' 
#' @export
#' @importFrom data.table rbindlist
collectData <- function(folderName, fileType = NULL, range = NULL, sheetIndex = 1){
  
  message('All the files in the folder should have the same format')
  
  if (is.null(fileType)) stop('Please enter fileType, "txt", "csv" or "excel".')
  
  if (length(range) > 4) {
    stop('"range" should be c(startRow, endRow, startCol, endCol)')
  }else if (is.null(range)) {
    stop('"range" can not be blank, e.g., range <- c(startRow, endRow, startCol, endCol).')
  }
  
  if (fileType == 'csv') {
    fileNames <- list.files(folderName, pattern = '*.csv', full.names = TRUE)
    if (length(fileNames) == 0) stop('No csv file in the folder.')
    
    data <- lapply(fileNames, readCsv, range = range)
    data <- rbindlist(data)
    
  } else if (fileType == 'txt') {
    fileNames <- list.files(folderName, pattern = '*.txt', full.names = TRUE)
    if (length(fileNames) == 0) {
      fileNames <- list.files(folderName, pattern = '*.TXT', full.names = TRUE)
    }
    if (length(fileNames) == 0) stop('No text file in the folder.')
    message('For txt file, only startRow and endRow will be considered.')
    data <- lapply(fileNames, readTxt, range = range)
    data <- unlist(data)
    
#   In order not to introduce too much trouble to user, this part has been hiden
#   Because it needs java environment installed.
#
  } else if (fileType == 'excel') {
    
    message('This part needs java installed in your computer, so it is commentted in
            the original file, check the original R file or https://github.com/Yuanchao-Xu/hyfo/blob/master/R/collectData.R
            for ideas.')
#     fileNames <- list.files(folderName, pattern = '*.xlsx', full.names = TRUE)
#     if (length(fileNames) == 0){
#       fileNames <- list.files(folderName, pattern = '*.xls', full.names = TRUE)
#     }
#     
#     if (length(fileNames) == 0) stop('No excel in the folder.')
#     data <- lapply(fileNames, readExcel, range = range, sheetIndex = sheetIndex)
#     checkBind(data, 'rbind')
#     data <- do.call('rbind', data)
  }else{
    stop('fileType should be "txt", "csv" or "excel".')
  }
  
  
  return(data)
  
}

# #importFrom xlsx read.xls
# readExcel <- function(fileName, range, sheetIndex){
#   data <- read.xls(fileName, sheetIndex = sheetIndex, rowIndex = seq(range[1], range[2]),
#                           colIndex = seq(range[3], range[4])) 
#   colnames(data) <- seq(1, dim(data)[2])
#   
#   message(fileName) 
#   return(data)
# }

readTxt <- function(fileName, range){
  data <- readLines(fileName)
  data <- data[range[1]:range[2]]
  return(data)
}



#' @importFrom utils read.csv
#' @references 
#' R Core Team (2015). R: A language and environment for statistical computing. R Foundation for
#' Statistical Computing, Vienna, Austria. URL https://www.R-project.org/.
readCsv <- function(fileName, range){
  
  data <- read.csv(fileName, skip = range[1] - 1, header = FALSE)
  data <- data[1:(range[2] - range[1] + 1), range[3]:range[4]]
  
  return(data)
}