An example to create, load, manipulate and save multiple csv files with R

load_and_save_multiple.r

### create some fictional data
dir.create("tmp")
setwd("tmp")
for(i in 1:10){
  tmp_file <- data.frame(x=1:100, y=rnorm(100), z = rnorm(100))
  tmp_file_name <- paste0(paste(letters[sample(1:24, 10)], collapse= ""), ".csv")
  write.csv(tmp_file, tmp_file_name, row.names= FALSE)
}


### The actual script

fileNames<-list.files()
my.data <- list()

for (i in 1:length(fileNames)){
  my.data[[i]] <- read.csv(fileNames[[i]],header=T)
}

## Create a function to do the job you want
write_indundated_file <- function(data_file, file_name){
  ## Calculate everything you want to
  non_inundated <- data_file[,2]/10000
  inundated <- data_file[,3]/10000
  Total_area <- non_inundated+inundated
  inundated_percent <- inundated/Total_area*100
  tmp <- data.frame(non_inundated, inundated, Total_area, inundated_percent)
  write.csv(tmp, file = file_name, row.names=FALSE)
}

for(i in 1:length(fileNames)){
  write_indundated_file(my.data[[i]], fileNames[[i]])
}

## load the files and check that they have been modified correctly

for (i in 1:length(fileNames)){
  my.data[[i]] <- read.csv(fileNames[[i]],header=T)
}

head(my.data[[1]])