coursera data scientist tool box

pollutantmean <- function(directory=getwd("C:/Users/larry/Desktop/specdata"), pollutant, id = 1:332) {

• fileList = list.files(path)
  

• file_names = as.numeric(sub("\\.csv$","",fileList))
  

• selected_files = fileList[match(id,file_names)]
  

• pollutantData = lapply(file.path(path,selected_files),read.csv)
  

• pollutantData = do.call(rbind.data.frame,pollutantData)
  

• mean(pollutantData[,pollutant],na.rm=TRUE)
  

• }