How to use R to Iterate through Subfolders and bind CSV files of the same ID?

Question

I am stuck. I need a way to iterate through a bunch of subfolders in a directory, pull out 4 .csv files , bind the contents of those 4 .csv files, then write out the new .csv to a new directory using the name of the initial subfolder as the name of the new .csv.

I know R could do this. But I am stuck at how to iterate across the subfolders and bind the csv files together. My obstacle is that each subfolder contains the same 4 .csv files using the same 8-digit id. For example, subfolder A contains 09061234.csv, 09061345.csv, 09061456.csv, and 09061560.csv. subfolder B contains 9061234.csv, 09061345.csv, 09061456.csv, and 09061560.csv. (...). There are 42 subfolders, and hence 168 csv files with the same names. I want to compact the files down to 42.

I can use list.files to retrieve all the subfolders. But then what?

##Get Files from directory
TF = "H:/working/TC/TMS/Counts/June09" 
##List Sub folders
SF <- list.files(TF)
##List of File names inside folders
FN <- list.files(SF)
#Returns list of 168 filenames

###?????###
#How to iterate through each subfolder, read each 8-digit integer id file, 
#bind them all together into one single csv, 
#Then write to new directory using 
#the name of the subfolder as the name of the new csv?

There is probably a way to do this easily but I am a noob with R. Something involving functions, paste and write.table perhaps? Any hints/help/suggestions is greatly appreciated. Thanks!

Answer 1

You can use recursive=T option for list.files,

 lapply(c('1234' ,'1345','1456','1560'),function(x){
     sources.files  <- list.files(path=TF,
                                recursive=T,
                                pattern=paste('*09061*',x,'*.csv',sep='')
                                ,full.names=T)
      ## ou read all files with the id and bind them
      dat <- do.call(rbind,lapply(sources.files,read.csv))
      ### write the file for the 
      write(dat,paste('agg',x,'.csv',sep='')
   }

Answer 2

After some tweaking of agstudy's code, I came up with the solution I was ultimately after. There were a couple of missing pieces that are more due to the nature of my specific problem, so I am leaving agstudy's answer as "accepted".

Turns out a function really wasn't needed. At least not for now. If I need to perform this same task again, I will create a function out of it. For now, I can solve this particular problem without it.

Also, for my instance, I needed a conditional "if" statement to handle any non-csv files that may have lived in the subfolders. By adding an if statement, R throws warnings and skips any files that are not comma-separated.
Code:

##Define directory path##
TF = "H:/working/TC/TMS/Counts/June09" 
##List of subfolder files where file name starts with "0906"##
SF <- list.files(TF,recursive=T, pattern=paste("*09061*",x,'*.csv',sep=""))
##Define the list of files to search for##
x <- (c('1234' ,'1345','1456','1560')
##Create a conditional to skip over the non-csv files in each folder##
if (is.integer(x)){
  sources.files  <- list.files(TF, recursive=T,full.names=T)}

dat <- do.call(rbind,lapply(sources.files,read.csv))
#the warnings thrown are ok--these are generated due to the fact that some of the folders contain .xls files
write.table(dat,file="H:/working/TC/TMS/June09Output/June09Batched.csv",row.names=FALSE,sep=",")