iOS Programming: The Big Nerd Ranch Guide, 6th Edition

For the More Curious: Reading and Writing to the Filesystem

In addition to archiving and Data’s binary read and write methods, there are a few more methods for transferring data to and from the filesystem. One of them, Core Data, is coming up in Chapter 22. A couple others are worth mentioning here.

Using Data works well for binary data. For text data, String has two instance methods: write(to:atomically:encoding:) and init(contentsOf:encoding:). They are used as follows:

// Save someString to the filesystem do { try someString.write(to: someURL, atomically: true, encoding: .utf8) } catch { print("Error writing to URL: \(error)") } // Load someString from the filesystem do { let myEssay = try String(contentsOf: someURL, encoding: ...