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

Posted by Alex Luo
Alex Luo
825 Points

Problems with "Working with Swift Statements"

I'm getting the following error message with this code:

Playground execution failed:

error: CollectionsAndControlFlows.playground:124:10: error: expression pattern of type 'String' cannot match values of type 'Dictionary<String, String>.Keys' case "BEL","LIE","BGR": europeanCapitals.append(value) ^~~~~

Code:

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 world { case "BEL","LIE","BGR": europeanCapitals.append(value) case "IND","VNM": asianCapitals.append(value) case "USA","MEX","BRA": otherCapitals.append(value) default:otherCapitals.append(value) } // End code }

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

    // End code
}

1 Answer

Tom Makedonski
Tom Makedonski
439 Points
Tom Makedonski
Tom Makedonski
439 Points

Your problem is that you can't switch on "word" (which is a dictionary). You have to switch on "key"(which is of type string):

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 "BEL","LIE","BGR": europeanCapitals.append(value)
    case "IND","VNM": asianCapitals.append(value)
    case "USA","MEX","BRA": otherCapitals.append(value)
    default:otherCapitals.append(value) }
// End code

}

europeanCapitals.forEach({print($0)})
print("\n")

asianCapitals.forEach({print($0)})
print("\n")

otherCapitals.forEach({print($0)})
print("\n")