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iOS Error Handling in Swift 2.0 Error Handling Handling Errors

Michael Reining
Michael Reining
10,101 Points
Posted by Michael Reining
Michael Reining
10,101 Points

Stuck with Part 1 of Challenge

Not sure what I am doing wrong in this code challenge.

Can someone please take a look at my code and let me know why it is not letting me pass the first step of the challenge?

enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

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

    func parse() throws {
        if data == nil { // Part 1 - if data is nil throw empty dictionary error
            ParserError.EmptyDictionary
        } else {
            // Part 2 - if someKey does not exist, throw invalid key error
            if ((data!.keys.contains("someKey")) == false) { 
                ParserError.InvalidKey
            }
        }

    }
}

let data: [String : String?]? = ["someKey": nil]
let parser = Parser(data: data)
error.swift 
enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

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

    func parse() throws {
        if data == nil {
            ParserError.EmptyDictionary
        } else {

            if ((data!.keys.contains("someKey")) == false) {
                ParserError.InvalidKey
            }
        }

    }
}

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

2 Answers

macserwicki
macserwicki
8,072 Points
macserwicki
macserwicki
8,072 Points

Here is the answer for Part 2. You're only missing the do{} part.

enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

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

    func parse() throws {
        guard let data = data else {
            throw ParserError.EmptyDictionary
        }

        guard let key = data["somekey"] else {
            throw ParserError.InvalidKey
        }

    }
}

let data: [String : String?]? = ["someKey": nil]
do {
let parser = try Parser(data: data) 
try parser.parse() 
} catch { }

Part 3 Answer Below. Try it on your own before copying :) Just add your 2 error types to the catch{}.

//

//

//

//

//

//

do {
let parser = try Parser(data: data) 
try parser.parse() 
} catch { ParserError.EmptyDictionary } 
catch {
ParserError.InvalidKey
}
Antonija Pek
Antonija Pek
5,819 Points
Antonija Pek
Antonija Pek
5,819 Points

I've stuck on part 2 of this challenge.

My code for first task passed but returned errors in second part.

enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

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

    func parse() throws {
        guard let data = data else {
            throw ParserError.EmptyDictionary
        }

        guard let key = data["somekey"] else {
            throw ParserError.InvalidKey
        }

    }
}

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

Someone help us!

Evans Attafuah
Evans Attafuah
18,277 Points
Evans Attafuah
Evans Attafuah
18,277 Points

this is my answer and it worked 

enum ParserError: ErrorType {
  case EmptyDictionary
  case InvalidKey
}

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

  func parse() throws {
    guard let _ = data else {
      throw ParserError.EmptyDictionary
    }

    guard let _ = data!["somekey"] else {
      throw ParserError.InvalidKey
    }

  }
}

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

do {
  try parser.parse()
} catch ParserError.EmptyDictionary {
  print("empty dictionary")
} catch ParserError.InvalidKey {
  print("missing key")
}