How to append fast updating strings to file in swift

Question

I want to write sensor data to a file as the sensor updates within the method. I need to append the data as it updates, but my file overwrites with the last sensor output when I

Answer 1

Use seekToEndOfFile

let myHandle = FileHandle.init(forWritingAtPath: fileUrl.path)

myHandle.seekToEndOfFile 

myHandle.write(strTowrite.data(using: String.Encoding.utf8)!)

myHandle.closeFile()