How can I read a file in a swift playground

Question

Im trying to read a text file using a Swift playground with the following

let dirs : String[]? =    NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory         


        

Answer 1

1. Select the .playground file.

2. Open Utility inspector, In the playground press opt-cmd-1 to open the File Inspector. You should see the playground on the right. If you don't have it selected, press cmd-1 to open the Project Navigator and click on the playground file.

3. Under 'Resource Path' in Playground Settings choose 'Relative To Playground' and platform as OSX.

Answer 2

1. Access a file that is located in the Resources folder of your Playground

With Swift 3, Bundle has a method called url(forResource:withExtension:). url(forResource:withExtension:) has the following declaration:

func url(forResource name: String?, withExtension ext: String?) -> URL?

Returns the file URL for the resource identified by the specified name and file extension.

You can use url(forResource:withExtension:) in order to read the content of a json file located in the Resources folder of an iOS or Mac Playground:

import Foundation

do {
    guard let fileUrl = Bundle.main.url(forResource: "Data", withExtension: "json") else { fatalError() }
    let data = try Data(contentsOf: fileUrl)
    let json = try JSONSerialization.jsonObject(with: data, options: [])
    print(json)
} catch {
    print(error)
}    

You can use url(forResource:withExtension:) in order to read the content of a text file located in the Resources folder of an iOS or Mac Playground:

import Foundation

do {
    guard let fileUrl = Bundle.main.url(forResource: "Text", withExtension: "txt") else { fatalError() }
    let text = try String(contentsOf: fileUrl, encoding: String.Encoding.utf8)
    print(text)
} catch {
    print(error)
}

As an alternative to let image = UIImage(named: "image"), you can use url(forResource:withExtension:) in order to access an image located in the Resources folder of an iOS Playground:

import UIKit

do {
    guard let fileUrl = Bundle.main.url(forResource: "Image", withExtension: "png") else { fatalError() }
    let data = try Data(contentsOf: fileUrl)
    let image = UIImage(data: data)
} catch {
    print(error)
}

---

2. Access a file that is located in the ~/Documents/Shared Playground Data folder of your computer

With Swift 3, PlaygroundSupport module provides a global constant called playgroundSharedDataDirectory. playgroundSharedDataDirectory has the following declaration:

let playgroundSharedDataDirectory: URL

The path to the directory containing data shared between all playgrounds.

You can use playgroundSharedDataDirectory in order to read the content of a json file located in the ~/Documents/Shared Playground Data folder of your computer from an iOS or Mac Playground:

import Foundation
import PlaygroundSupport

do {
    let fileUrl = PlaygroundSupport.playgroundSharedDataDirectory.appendingPathComponent("Data.json")        
    let data = try Data(contentsOf: fileUrl)
    let json = try JSONSerialization.jsonObject(with: data, options: [])
    print(json)
} catch {
    print(error)
}

You can use playgroundSharedDataDirectory in order to read the content of a text file located in the ~/Documents/Shared Playground Data folder of your computer from an iOS or Mac Playground:

import Foundation
import PlaygroundSupport

do {
    let fileUrl = PlaygroundSupport.playgroundSharedDataDirectory.appendingPathComponent("Text.txt")
    let text = try String(contentsOf: fileUrl, encoding: String.Encoding.utf8)
    print(text)
} catch {
    print(error)
}

You can use playgroundSharedDataDirectory in order to access an image located in the ~/Documents/Shared Playground Data folder of your computer from an iOS Playground:

import UIKit
import PlaygroundSupport

do {
    let fileUrl = PlaygroundSupport.playgroundSharedDataDirectory.appendingPathComponent("Image.png")
    let data = try Data(contentsOf: fileUrl)
    let image = UIImage(data: data)
} catch {
    print(error)
}

Answer 3

Swift 3 (Xcode 8)

The code below works in both iOS and macOS playgrounds. The text file ("MyText.txt" in this example) must be in the Resources directory of the playground. (Note: You may need to open the navigator window to see the directory structure of your playground.)

import Foundation

if let fileURL = Bundle.main.url(forResource:"MyText", withExtension: "txt")
{
    do {
        let contents = try String(contentsOf: fileURL, encoding: String.Encoding.utf8)
        print(contents)
    } catch {
        print("Error: \(error.localizedDescription)")
    }
} else {
    print("No such file URL.")
}