How to change array value depend on condition in Swift? - ios

Question

I have array like this
var country = ["America","Germany","China"]
My need is if this array have America
I would like to make it become "US"
hoping result like this
["US","Europe","Asia"]
don't use country[0] = "US"
because array order every times are different
Use condition that I gave
How should I do ?

Answer 1

Create a dictionary of what a string in countries needs to be replaced with.
let countriesToRegions = ["America": "US", "Germany": "Europe", "China": "Asia"]
Then when you need to convert the countries into regions, you can look them up in the dictionary.
var countries = ["America", "Germany", "China"]
let regions = countries.map { country in
countriesToRegions[country] ?? country
}
The last bit here, ?? country, is handling the possibility that the country is not in the countriesToRegions dictionary.

Answer 2

Here is one way to do it (comments inline):
let country = ["USA", "Germany", "China", "Fakeland"]
// use a dictionary for the replacements
let continentForCountry = ["USA": "North America", "Germany": "Europe", "China": "Asia"]
// use map to replace each item and set a default value if the
// replacement is not found
let result = country.map { continentForCountry[$0, default: "unknown continent"] }
print(result)
["North America", "Europe", "Asia", "unknown continent"]

Answer 3

Try -
let requiredIndex = country.index(where: { $0 is "America" }) {
country[requiredIndex] = "US"
}

Answer 4

You can either use Map or for a more explained version, can use the below function
func replaceOccuranceInArray(inArray:[String], of originalString: String, with replacementString: String) -> [String] {
var arrayToBeReturned = inArray
var indexes = [Int]()
for currentIndex in 0...inArray.count - 1 {
if inArray[currentIndex] == originalString {
indexes.append(currentIndex)
}
}
for eachIndex in indexes {
arrayToBeReturned[eachIndex] = replacementString
}
return arrayToBeReturned
}
I have attached a Playground output for the same below

Answer 5

As some suggested, you can use power of .map function.
Here is simple solution how you can map country to continent:
let americanCountries = ["US", "Argentina", "Brasil"]
let asianCountries = ["China", "Japan", "Korea"]
let europeanCountries = ["Germany", "France", "Spain"]
let countries = ["US","Germany","China"]
let continents = countries.map { country -> String in
if americanCountries.contains(country) {
return "America"
} else if asianCountries.contains(country) {
return "Asia"
} else if europeanCountries.contains(country) {
return "Europe"
} else {
return "Unknown continent"
}
}
Another step would be try to use enums.

Answer 6

A simple solution :
Get the index of the value to be replaced and replace it if existing:
if let ind = country.firstIndex(of: "America"){
country[ind] = "US"
}