Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

iOS Error Handling in Swift 2.0 Error Handling Handling Errors

error handling error

can't compile the handling error from dictionary

error.swift
enum ParserError: ErrorType {
  case EmptyDictionary
  case InvalidKey
}

struct Parser {
  var data: [String : String?]?

  func parse() throws {
guard var data = dict[data] else {
throw ParserError.EmptyDictionary
}
guard var data = dict["somekey"] else {
throw ParserError.InvalidKey
}
  }
}

let data: [String : String?]? = ["someKey": nil]
let parser = Parser(data: data)

4 Answers

Konrad Król
Konrad Król
4,454 Points

Nope. It works perfectly fine for challenge task 1 of 3:

enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

struct Parser {
    var data: [String : String?]?

    func parse() throws {
        if let someDict = data {
            if let someData = someDict["someKey"]{
                //code here
            } else {
            throw ParserError.InvalidKey
            }
        }
        else {
        throw ParserError.EmptyDictionary
        }

    }
}

let data: [String : String?]? = ["someKey": nil]
let parser = Parser(data: data)
Konrad Król
Konrad Król
4,454 Points

Hi, first you should check if data in dictionary exists if FALSE you throw an error .EmptyDictionary if TRUE you check if value for "someKey" exists, and again if FALSE throw an error .InvalidKey like this:

struct Parser {
    var data: [String : String?]?

    func parse() throws {
        if let someDict = data {
            if let someData = someDict["someKey"]{
                // TRUE statement code is not required here
            } else {
            throw ParserError.InvalidKey
            }
        }
        else {
        throw ParserError.EmptyDictionary
        }      
    }
}

thks but still giving me a ton of errors

yes, Don't know what was going on. thks Mate!