Soemthing along these lines should work, haven't run it myself.
library(data.table)
patternstomatch <- gsub(list.files(), pattern = ".csv", replacement = "")
for (i in patternstomatch)
{
filestorbind <- list.files(pattern = i)
if( length(filestorbind ) > 1)
{
rbindeddataset <- rbindlist(lapply(filestorbind, read.csv))
write.csv(rbindeddataset , file = paste(i,".csv", sep = ""))
}
}
patternstomatch will contain "2013-09-13(1)","2013-09-13","2013-09-14", etc. the loop will look for each of these strings in the filenames. If multiple files are found matching a pattern it will read them all, rbind them and write it out as ".csv".
Using the gsub approach on the first line, you can then find files that have "(" in their file name and use file.remove to delete those files.