R utility methods

lib.R

# Collected R utility methods

read_all_csv_files <- function(dir) {
  save_dir <- getwd()
  setwd(dir)
  files <- list.files(pattern = "csv")
  for (file in files) {
    if (!exists("dataset")){ 
      dataset <- read.csv(file) 
    } else {
      temp_dataset <- read.csv(file, stringsAsFactors = FALSE)
      dataset <- rbind(dataset, temp_dataset)
      rm(temp_dataset)
    }
  }
  setwd(save_dir)
  return(dataset)
}

# convert datetimestamps
convert_date <- function(var) {
  var <- as.character(var)
  var[var == ""] <- NA
  var <- as.POSIXct(var)
  return(var)
}

# return the last item from a vector v, as identified by dates in vector dates
last_item <- function(v, dates) {
  if (sum(!is.na(dates))==0) { return(NA) }
  return(v[which(dates == max(dates, na.rm = TRUE))])
}

# last_item(c("wrong","right","wrong"), as.POSIXct(c("2018-01-02","2018-12-31","2018-01-01")))
# last_item(c("wrong","wrong"),c(NA, NA))