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

Tim Seme
Tim Seme
1,664 Points

hey im super confused can u help me out

this is what it tells me to do but i dont fully understand

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",// eur
  "LIE": "Vaduz",// eur
  "BGR": "Sofia",// eur
  "USA": "Washington D.C.", 
  "MEX": "Mexico City", 
  "BRA": "Brasilia",// eur
  "IND": "New Delhi",// eur
  "VNM": "Hanoi"]//asian

for (key, value) in world {
    // Enter your code below
    switch europeanCapitals.append(world){
    case "BEL": print("Brusels")
    case "LIE": print("Vaduz")
    case "BGR": print("Sofia")
    case "BRA": print("Brasilia")
    case "IND": print("New Delhi")
    }
    switch asianCapitals.append(world){
    case "VNM": print("Hanoi")
    }
    switch otherCapitals.append(world){
    case "USA": print("Washington D.C.")
    case "MEX": print("Mexico City")
    }
    // End code
}

1 Answer

Hi Tim,

You want to switch on the key. Then, for each potential key, append value into the relevant array. You do that inside each case. You can handle multiple cases in one line.

Here's a little hint rather than the whole code:

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

I hope that helps,

Steve.

To clarify, the for loop is going through each member of the world dictionary. It parses over each element and makes kay and value available within the loop as local variables of the same name. At each iteration, you search for th key and, if found, you append it to the correct array. As you have used the key to identify the record you want to handle, you append the corresponding value that the key gives you access to.

Make sense?

Steve.