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iOS Error Handling in Swift 2.0 Error Handling Handling Errors

Posted by Oliver Duncan
Oliver Duncan
16,642 Points

Not sure how to check if key does not exist.

I'm not sure how to use the contains method on the data.keys array to check if the key exists.

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

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

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

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

1 Answer

Krzysztof Growinski
Krzysztof Growinski
8,405 Points

Hi, try this:

if data.keys.contains("someKey") {

} else { throw ParserError.InvalidKey }

Oliver Duncan
Oliver Duncan
16,642 Points

Ah, they were asking to literally pass in "someKey". I missed that by a mile. Thanks!