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Start your free trialMaxwell Catmur
7,355 Pointshow do I append switch statements inside of for loops to arrays when dealing with capital cities?
Please can someone help me with this code challenge? Here is the question:
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.
The code is below: Please can you let me know where I went wrong? Thanks
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, value) {
case "BEL", "Brussels": europeanCapitals.append[]
case "LIE", "Vaduz": europeanCapitals.append[]
case "BGR", "Sofia": europeanCapitals.append[]
case "USA", "Washington D.C": otherCapitals.append[]
case "MEX", "Mexico City": otherCapitals.append[]
case "BRA", "Brasilia": otherCapitals.append[]
case "IND", "New Delhi": asianCapitals.append[]
case "VNM", "Hanoi": asianCapitals.append[]
}
// End code
}
2 Answers
Steve Hunter
57,712 PointsHi Maxwell,
You are pretty much there with this. There's just a couple of points to fix.
First, switch
just on the key
. You want to append()
(round brackets!) the value
to the relevant array when the key
matches. Pass the value
into the append()
method - arrayName.append(value)
.
You can also have multiple case
matches.
So, here's a clue:
switch key{
case "BEL", "LIE", "BGR": europeanCities,append(value)
// further cases here!
}
Think about the default case too.
Let me know how you get on!
Steve.
Steve Hunter
57,712 PointsHI Andrew,
The posts in this thread cover your issue. But first, don't amend the code the challenge presents you with. Restart the challenge.
Then, just switch on the key
and use append()
to add the value
to the respective array.
So you get:
for (key, value) in world{
}
Switch on key
and append value
. Like:
switch key{
case "BEL", "LIE", "BGR": europeanCities,append(value)
// further cases here!
}
Make sense?
Steve.
Maxwell Catmur
7,355 PointsMaxwell Catmur
7,355 PointsGreat! Thank you very much!
Steve Hunter
57,712 PointsSteve Hunter
57,712 PointsNo problem!
Andrew Bergsma
880 PointsAndrew Bergsma
880 PointsI'm stumped on this one.. I keep trying every which way and the compiler keeps returning the error "Expression pattern of type 'String' cannot match values of type '(key: String, value: String)" and extra call in argument. Please help! thanks
Steve Hunter
57,712 PointsSteve Hunter
57,712 PointsCan you post your code, Andrew?
Andrew Bergsma
880 PointsAndrew Bergsma
880 PointsWhat am I doing wrong here? https://teamtreehouse.com/library/swift-collections-and-control-flow/control-flow-with-conditional-statements/working-with-switch-statements
[MOD: edited code block - srh]