In Swift 3, how to fix an error about argument labels do not match any available overloads for String type? [duplicate]

Question

In Swift 2, I could load data from somefile.txt as the code below without problem:

let fileManager = FileManager.default
let urls = fileManager.urls(for: .applicationSupportDirectory, in: .userDomainMask)
let appDataURL = urls.last.appendingPathComponent("appData")

let fileDestinationUrl = appDataURL!.appendingPathComponent("somefile.txt")

var dataString = ""
do {
    dataString = try String(contentsOfURL: fileDestinationUrl)  //<-- error here
    print("dataString=\(dataString)")
} catch let error as NSError {
    print("Failed reading data in appData Directory, Error: \(error.localizedDescription)")
}

However, in Swift 3, XCode gives an error at line dataString = try String(contentsOfURL: fileDestinationUrl) by saying:

Argument labels '(contentsOfURL:)' do not match any available overloads

How to fix this error? What is the right way to read the text file in Swift 3?

Answer 1

This method has been updated to (in the context of your example):

dataString = try String(contentsOf: fileDestinationUrl) 

In Swift 3, all function params now have labels unless specifically defined otherwise. This in practice often means the last part of a method name moves to the first params label.