How can I split an array into specified lines when printing? - swift

Question

New to software development, I'm working through Big Nerd Ranch's book 'Swift Programming'. One of the challenges set by the book is to print an array within a dictionary that contains 15 zip codes and to have them split across three lines in groups of five. The formatting must exactly match how it appears in the book.
I have tried to solve the issue using the information taught in the book with assistance from the developer documentation.
No dice.
This is what I need to print:
Caterham has the following zip codes: [111, 111, 111, 111, 111,
222, 222, 222, 222, 222,
333, 333, 333, 333, 333]
However this is the closest I can get...
var areaCodes = ["Caterham": [111, 111, 111, 111, 111], "Coulsdon": [222, 222, 222, 222, 222], "Purley": [333, 333, 333, 333, 333]]
var caterhamCodes : [Int] = []
for (_, values) in areaCodes {
caterhamCodes += values
}
print("Caterham has the following codes: \(caterhamCodes[0...4]),")
print(" \(caterhamCodes[5...9]),")
print(" \(caterhamCodes[10...14]).")
which prints:
Caterham has the following postcodes: [111, 111, 111, 111, 111],
[222, 222, 222, 222, 222],
[333, 333, 333, 333, 333].
Essentially, I need what I have above minus some square brackets and without the punctuation after each time a block of zip codes is printed. The book specifies that I might need to use a parameter called terminator. It also mentions I might need to learn how to represent special characters in string literals.
I appreciate that this is probably a high level question with a simple answer, but I'm only a few weeks into learning, so I hope I can be forgiven for asking at least a few silly questions!

Answer 1

Welcome to the developer community and have a nice stay!
I am trying to put answer as simple as possible, so here is my attempt:
var areaCodes = ["Caterham": [111, 111, 111, 111, 111],
"Coulsdon": [222, 222, 222, 222, 222],
"Purley": [333, 333, 333, 333, 333]]
let codesArray = areaCodes.values.sorted(by: { $0[0] < $1[0] })
let caterhamString = "Caterham has the following zip codes: ["
var printString = caterhamString
for (index, area) in codesArray.enumerated() {
for code in area {
printString += "\(code), "
}
if index != codesArray.count - 1 {
printString += "\n" + String(repeating: " ", count: caterhamString.count)
}
}
print(printString.dropLast(2).appending("]"))
Hope this helps! Good luck!

Answer 2

Here is a way of getting the desired output :
let intro = "Caterham has the following zip codes: ["
let spaces = ",\n" + String(repeating: " ", count: intro.count)
let areaCodes = ["Caterham": [111, 111, 111, 111, 111], "Coulsdon": [222, 222, 222, 222, 222], "Purley": [333, 333, 333, 333, 333]]
let codes = areaCodes.values.sorted { $0[0] < $1[0] }
var output = intro +
codes.map { $0.map{ String($0) }.joined(separator: ", ") }
.joined(separator: spaces)
+ "]"
print(output)
Which prints
Caterham has the following zip codes: [111, 111, 111, 111, 111,
222, 222, 222, 222, 222,
333, 333, 333, 333, 333]