Working with Switch statements

Hi Giovanni,

Your mind is on the right path, but there are some issues with how you've used the switch statement. Also, you are appending the right values into the arrays, but you are not doing it correctly. I'll explain.

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.

What they are asking is for you to append the value of each key within the world dictionary to the appropriate "capitals" array. Notice the for-in loop they provided for you has a key and value constant defined

for (key, value) in world { ...

For every iteration on the world dictionary, they key/value constants will hold values for the item it pulled from the dictionary on that iteration. When we look at your implementation, you'll notice it is appending a string literal instead of using the for loop's local value variable. It works, but it's prone to error because you aren't pulling values from the actual dictionary you are iterating over and instead you have redefined the correct values as new string literals. Also, the compiler will complain that you have an unused local variable (value). So, you'll want to fix this like so...

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

Now, everytime the for-in loop iterates on the world dictionary, it will hit the switch statement and evaluate key, then when a case is matched, it will append the actual value of that dictionary key with the value variable.

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.

Again, you're on the right path for what they are asking, but the implementation is incorrect. The other problem is with your switch statement's default case. Notices what Apple says about default cases...

Every switch statement must be exhaustive. That is, every possible value of the type being considered must be matched by one of the switch cases. If it’s not appropriate to provide a case for every possible value, you can define a default case to cover any values that are not addressed explicitly.

A default case is the "catch all" for any cases that were not defined in the switch statement. That means you don't have to, nor can you, explicitly define cases to match for a default case. So, let's change that.

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

So, now the switch statement will hit the default case for any keys that do not match the other cases you explicitly defined above it without exhaustively defining them yourself. If you did want to exhaustively define the switch cases, you would not use a default. However, that's not what the challenge is asking for.

Our code should now look like this.

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

I hope this was helpful. I would suggest watching/reading more on control flow. Apple's Swift documentation is always a great place to start.