This content originally appeared on DEV Community and was authored by John Kevin Losito
Arrays, dictionaries, sets, and enums
https://www.hackingwithswift.com/100/swiftui/3
Array
Swift has a way of storing ordered lists of values of the same type, known as Array. There are three ways of declaring an array.
var trainers = ["Ash", "Brock", "Misty"]
var numbers = [1, 29, 45]
var grades = [95.2, 86.8, 90.1]
var pokemonRegions = [String]()
var pokemonSpecies = Array<String>()
You access data from an array using its index, which starts at 0.
print(trainers[0])
You can add items to an array using append method.
var pokemonTypes = Array<String>()
pokemonTypes.append("Fire")
pokemonTypes.append("Water")
pokemonTypes.append("Grass")
print(pokemonTypes)
Arrays also has other useful methods.
print(trainers.count)
trainers.remove(at: 2)
print(trainers.count)
print(trainers)
print(pokemonTypes.contains("Ice"))
print(pokemonTypes.sorted())
Dictionaries
Dictionaries store items as key-value pair. The left part(before semicolor) is the key and the right part is the value.
let pokemon = [
"name": "Charizard",
"type": "Fire",
"ability": "blaze"
]
You access the data using its key, not the index. When reading from a dictionary, you can provide a default value to use if the key doesn’t exist.
print("Name: \(pokemon["name", default: "Unknown"])")
print("Name: \(pokemon["type", default: "Unknown"])")
print("Name: \(pokemon["ability", default: "Unknown"])")
You can also create an empty dictionary and add items after.
var regionGeneration = [String: Int]()
regionGeneration["Kanto"] = 1
regionGeneration["Johto"] = 2
regionGeneration["Hoenn"] = 3
Sets
Sets are like array but stores an unordered list of unique elements. Meaning, the orders are not guaranteed, and elements should not be duplicated.
let emails = Set(["test@email.com", "juan@email.com", "sample@email.com",])
print(emails)
You add items to set using insert method.
var pokemons = Set<String>()
pokemons.insert("Pikachu")
pokemons.insert("Charmander")
pokemons.insert("Dragonite")
print(pokemons)
Enum
An enumeration or enum defines a common type for a group of related values. You declare enum in two ways:
enum Weekday {
case monday
case tuesday
case wednesday
case thursday
case friday
}
enum Element {
case fire, water, earth, wind
}
You use enum this way:
var day = Weekday.friday
print(day)
var element = Element.fire
print(element)
This content originally appeared on DEV Community and was authored by John Kevin Losito
John Kevin Losito | Sciencx (2022-03-20T15:34:37+00:00) Day 3: 100 Days of SwiftUI. Retrieved from https://www.scien.cx/2022/03/20/day-3-100-days-of-swiftui/
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