setwd("C:/.../dir_of_files")
# directory name
# (the script assumes that the new directory is placed inside the working directory)
new_dir <- "my_name"
addition_to_file<- "whatever"
list_of_files <- list.files()
for (file1 in list_of_files){
tbl <- read.csv(file1)
# apply your function - 'f'
results <- f(tbl)
# remove .csv extension from file name
file1_nocsv <- unlist(strsplit(file1,".csv", fixed = TRUE))
# the name of the new file
new_file_name <- paste(new_dir,"/",file1_nocsv,"_",addition_to_file,".csv", sep = "")
# write 'results' to
write.csv( results, file = new_file_name )
}