Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Error Handling in Swift Error Handling Handling Errors

Help needed!

I need help to solve this

enum ParserError: Error {
  case emptyDictionary
  case invalidKey
}

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

  func parse() throws {

  }
}

let data: [String : String?]? = ["someKey": nil]
let parser = Parser(data: data)
Bruce Röttgers
Bruce Röttgers
18,211 Points

could you please format your code (refer to the markdown cheatsheet right before the post button for details (you need three backticks at the start and end

2 Answers

Here is my answer that passes all three parts of the challenge.

enum ParserError: Error {
    case emptyDictionary
    case invalidKey
}

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

    func parse() throws {
        guard let data = data else {
            throw ParserError.emptyDictionary
        }
        guard data["someKey"] != nil else {
            throw ParserError.invalidKey
        }

    }
}

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

do {
    try parser.parse()
} catch ParserError.emptyDictionary {
    print("Error: EmptyDictionary")
} catch ParserError.invalidKey {
    print("Error: InvalidKey")
}

Thanks! I solved in this way if someone wants to see other option

enum ParserError: Error {
    case emptyDictionary
    case invalidKey
}

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

    func parse() throws {
        if data?.count == nil {
            throw ParserError.emptyDictionary
        }


        if data?.keys.contains("someKey") != nil {
            throw ParserError.invalidKey
        }
    }
}

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

do {
  try parser.parse()
}catch ParserError.emptyDictionary {
    print("Error: EmptyDictionary")
} catch ParserError.invalidKey {
    print("Error: InvalidKey")
}
FANG YU
FANG YU
1,719 Points
func parse() throws {
        guard let data = data else {
            throw ParserError.emptyDictionary
        }
        guard data.keys.contains("someKey") else {
            throw ParserError.invalidKey
        }
    }