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

Posted by Flora Yasmin
Flora Yasmin
485 Points

I understand the question, but I don't know how to do it.

In the editor we have a dictionary that contains a three letter country code as a key and that country's capital city as the associated value.

We also have three empty arrays, europeanCapitals, asianCapitals, and otherCapitals. The goal is to iterate through the dictionary and end up with just the names of the capital cities in the relevant array.

For example, after you execute the code you write, europeanCapitals will have the values ["Vaduz", "Brussels", "Sofia"] (not necessarily in that order).

To do this you're going to use a switch statement and switch on the key. For cases where the key is a European country, append the value (not the key!) to the europeanCapitals array. For keys that are Asian countries, append the value to asianCapitals and finally for the default case, append the values to otherCapitals.

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
}

2 Answers

Jerson Otzoy
Jerson Otzoy
1,532 Points
Jerson Otzoy
Jerson Otzoy
1,532 Points

Hello,

For this as it says you have to use a switch statement, if you don't know how to use it go and take a look to the documentation, basically you can evaluate multiple values for the cases separating with comma, like this, I leave you the second case for you to complete it, the asian capitals.

switch key {
    case "BEL", "LIE", "BGR":
        europeanCapitals.append(value)
    case (add the second cases here):

    default:
        otherCapitals.append(value)
    }
Flora Yasmin
Flora Yasmin
485 Points

This isn't really working... Can you please help a little bit more?

Flora Yasmin
Flora Yasmin
485 Points

I don't understand the value part. What do you put in the ()?

Flora Yasmin
Flora Yasmin
485 Points
Flora Yasmin
Flora Yasmin
485 Points

This isn't really working... Can you please help a little bit more?

Jerson Otzoy
Jerson Otzoy
1,532 Points
Jerson Otzoy
Jerson Otzoy
1,532 Points 
switch key {
    case "BEL", "LIE", "BGR":
        europeanCapitals.append(value)
    case "IND", "VNM":
        asianCapitals.append(value)
    default:
        otherCapitals.append(value)
    }
Flora Yasmin
Flora Yasmin
485 Points

what do you append?

Flora Yasmin
Flora Yasmin
485 Points

What is the value?