Deleting contents of text file

Question

I'm reading and writing to a text file. There is an instance where I want to delete the contents of the file (but not the file) as a kind of reset. How can I do this?

if ((dirs) != nil) {
    var dir = dirs![0]; //documents directory

    let path = dir.stringByAppendingPathComponent("UserInfo.txt");
    println(path)
    let text = "Rondom Text"

    //writing
    text.writeToFile(path, atomically: false, encoding: NSUTF8StringEncoding, error: nil)

    //reading
    let text2 = String(contentsOfFile: path, encoding: NSUTF8StringEncoding, error: nil)

    println(text2)

Woofer

Did you get any error with your code? – Smarten

Nothing wrong with the above code. I would just like to know how to delete the contents of the file... i.e. here I'm writing to the file and then the user presses reset, so the file becomes empty. – Woofer

"".writeToFile(path, atomically: false, encoding: NSUTF8StringEncoding, error: nil) The file will have cleared. – Smarten

If that solved your issue, please accept my answer :) – Smarten

Answer 1

Simply write an empty string to the file like this:

let text = ""
text.writeToFile(path, atomically: false, encoding: NSUTF8StringEncoding, error: nil)

Smarten

Answer 2

If you set up an NSFileHandle, you can use -truncateFileAtOffset:, passing 0 for the offset.

Or, as pointed out in comments, you can simply write an empty string or data to the file.

Or you can use some kind of data structure / database that does not require you to manually truncate files :)

Pressroom

Answer 3

Swift 3.x

let text = ""
do {
     try text.write(toFile: fileBundlePath, atomically: false, encoding: .utf8)
} catch {
     print(error)
}

Swift 4.x

let text = ""
do {
     try text.write(to: filePath, atomically: false, encoding: .utf8)
   } catch {
     print(error)
   }

Koh