How to delete/overwrite CSV file using google apps script? - google-apps-script

Question

My google apps script imports a csv file [test.csv] into a new tab, manipulates some values, then saves the manipulated tab as a csv file [test.csv]. When it saves the new version, it simply makes another copy [test(1).csv]. I wish instead to overwrite the previous file (or delete the old one then export/write the new version.) Help please?
I am using reference code from the Interacting With Docs List Tutorial

Answer 1

I know this is an old question, but much of the information in the accepted answer has been deprecated by Google since then. DocsList is gone, as are the clear() and append() methods on a file object.
I use the following function to create or overwrite a file:
// Creates or replaces an existing file
function updateFile (folder, filename, data) {
try {
// filename is unique, so we can get first element of iterator
var file = folder.getFilesByName(filename).next()
file.setContent(data)
} catch(e) {
folder.createFile(filename, data)
}
}
For reference, here's some code for doing the same for a folder. It assumes we're operating in the parent folder of the current sheet and want a folder
object for a new or existing folder there.
// Get folder under current folder. Create it if it does not exist
function getOrCreateFolder(csvFolderName) {
var thisFileId = SpreadsheetApp.getActive().getId();
var thisFile = DriveApp.getFileById(thisFileId);
var parentFolder = thisFile.getParents().next();
try {
// csvFolderName is unique, so we can get first element of iterator
var folder = parentFolder.getFoldersByName(csvFolderName).next();
// asking for the folder's name ensures we get an error if the
// folder doesn't exist. I've found I don't necessarily catch
// an error from getFoldersByName if csvFolderName doesn't exist.
fname = folder.getName()
} catch(e) {
var folder = parentFolder.createFolder(csvFolderName);
}
return folder
}

Answer 2

You could do DocsList.find(fileName) which gives you a list of files that have that name. If file names are unique, then you can just do var file = DocsList.find(fileName)[0].
If you are a Google Apps user, you can use file.clear() to remove all the contents of the old file, and then file.append() to insert all of the new contents.
Otherwise, you will have to file.setTrashed(true) and then DocsList.createFile() to make the new one.