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

Christiaan van Bastelaar
Christiaan van Bastelaar
10,063 Points
Posted by Christiaan van Bastelaar
Christiaan van Bastelaar
10,063 Points

Extract the key from a dictionary

How can I extract the key of a dictionary to have its value added to an array?

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 in world.keys {
    switch world {
        case  "BEL":  europeanCapitals.append("Brussels")
    }

}

1 Answer

Christian Mangeng
Christian Mangeng
15,970 Points
Christian Mangeng
Christian Mangeng
15,970 Points

Hi Christiaan,

1) You need to iterate over the key, value pairs in order to solve this task

for (key, value) in world {
    switch key {
    }
}

2) Note that you should compare only the keys of the dictionary with the switch cases, rather than the whole dictionary, so it should be "switch key".

3) Now you can compare each key like that and append the values of the corresponding keys to the correct lists:

case "BEL": europeanCapitals.append(value)

You could also append the keys that way, by using .append(key) instead of value, but the challenge does not ask for that.