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iOS Swift Collections and Control Flow Control Flow With Conditional Statements Working With Switch Statements

Posted by Eddie Aguilar
Eddie Aguilar
2,393 Points

cannot move past this

Cannot seem to figure out what is wrong, can some please explain what is not written correctly?

operators.swift 
var europeanCapitals: [String] = []
var asianCapitals: [String] = []
var otherCapitals: [String] = []

let world = [
  "BEL": "Brussels", 
  "LIE": "Vaduz", 
  "BGR": "Sofia", 
  "USA": "Washington D.C.", 
  "MEX": "Mexico City", 
  "BRA": "Brasilia", 
  "IND": "New Delhi", 
  "VNM": "Hanoi"]

for (key, value) in world {
    // Enter your code below
    switch key {
      case "LIE","BEL", "BGR" : europeanCapitals.append(value)
      case "VNM" : asianCapitals.append(value)
      case "USA", "MEX", "BRA", "IND" : otherCapitals.append(value)
      }


    // End code
}

1 Answer

Greg Kaleka
Greg Kaleka
39,021 Points
Greg Kaleka
Greg Kaleka
39,021 Points

Hi Eddie,

Note that when you submit your code it tells you it could not be compiled. If you click on the Preview button, you'll see this error:

error: switch must be exhaustive, consider adding a default clause

In Swift, you must cover every possible case with a switch statement. We need a default case, since we're comparing strings (note if you were checking an enum, Swift would know if you'd covered all options). We actually don't have to change much in your code - we can simply check for European capitals, Asian capitals, and if neither of those match, default to Other capitals:

var europeanCapitals: [String] = []
var asianCapitals: [String] = []
var otherCapitals: [String] = []

let world = [
  "BEL": "Brussels", 
  "LIE": "Vaduz", 
  "BGR": "Sofia", 
  "USA": "Washington D.C.", 
  "MEX": "Mexico City", 
  "BRA": "Brasilia", 
  "IND": "New Delhi", 
  "VNM": "Hanoi"]

for (key, value) in world {
    // Enter your code below
    switch key {
      case "LIE","BEL", "BGR" : europeanCapitals.append(value)
      case "VNM" : asianCapitals.append(value)
      default : otherCapitals.append(value)
      }
    // End code
}

Hopefully that makes sense!

Cheers :beers:

-Greg