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iOS Error Handling in Swift Error Handling Handling Errors

Richard Sun
Richard Sun
11,257 Points
Posted by Richard Sun
Richard Sun
11,257 Points

How do I get a list of keys in a dictionary?

I don't think this is my only problem in this coding challenge. It would be great to get some help! Also, I would like to know if my code part, where it checks if "someKey" exists, is correct.

error.swift 
enum ParserError: Error {
  case emptyDictionary
  case invalidKey
}

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

  func parse() throws {
    guard let hasKeys = data.keys else {
      throw ParserError.emptyDictionary
    }

    guard let someKey = data.contains["someKey"] else {
      throw ParserError.invalidKey
    }
  }
}

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

1 Answer

Jeff McDivitt
Jeff McDivitt
23,970 Points
Jeff McDivitt
Jeff McDivitt
23,970 Points

You are on the right track, let me know if you need further explanation

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


        }
    }
}
Richard Sun
Richard Sun
11,257 Points
Richard Sun
Richard Sun
11,257 Points

Oh that makes sense. Thanks a lot!