Pollutant Mean

Pollutant Mean Function

pollutantmean <- function(directory, pollutant, id = 1:332) {
  fileList <- list.files(path = directory, pattern = ".csv", full.names = TRUE)
  values <- numeric()
  
  for (i in id) {
    data <- read.csv(fileList[i])
    values <- c(values, data[[pollutant]])
  }
  mean(values, na.rm = TRUE)
}

Pollutant Mean Test Case

pollutantmean("/users/ChessTastic/Dropbox/github/coursera/R_programming/week_2/specdata/", "sulfate")

## [1] 3.189369