【Swift】enum(列挙型)の使い方！値型enumと関連型enumとは

enum Language {
    case html
    case css
    case php
    case swift
}

enum Language {
    case html,css,php,swift
}

enum Language {
    case html
    case css
    case php
    case swift
}

func printLang(lang: Language) {
        switch lang {

          case .html:
              print( "HELLO! HTML!" )
          case .css:
              print( "HELLO! CSS!" )
          case .php:
              print( "HELLO! PHP!" )
          case .swift:
              print( "HELLO! SWIFT!" )

        }
}

// 変数に列挙型の値を格納
let l = Language.swift
// 格納された列挙型の値により分岐
printLang(lang:l) // HELLO! SWIFT!

enum Language:Double{    
    case html
    case css
    case php
    case swift
}

// エラー
enum Language:Bool{    
    case html
    case css
    case php
    case swift
}

'Language' declares raw type 'Bool', but does not conform to RawRepresentable and conformance could not be synthesized
Raw type 'Bool' is not expressible by a string, integer, or floating-point literal
// 'Language'はraw型'Bool'を宣言しますが、RawRepresentable(※1)に準拠しておらず、準拠を合成できませんでした
// 生の型'Bool'は、文字列、整数、または浮動小数点リテラルでは表現できません

enum Language:Double {
    case html = 5.0
    case css = 3.0
    case php = 8.1
    case swift = 5.4
}

var lang = Language.html
print(lang) // html
type(of: lang) // Language.Type

var lang2 : Language // enum型名で宣言しておく
lang2 = .html

lang = Language.fromRaw(0)

var langHtml = Language.html
langHtml.rawValue // 5

enum Language:Double {
    case html
    case css
    case php
    case swift
}

Language.html.rawValue // 0
Language.css.rawValue // 1
Language.php.rawValue // 2
Language.swift.rawValue // 3

enum Framework:String{
    case Perfect
    case Slimane
    case Swifton
    case Vapor
}

Framework.Perfect.rawValue // Perfect
Framework.Slimane.rawValue // Slimane
Framework.Swifton.rawValue // Swifton
Framework.Vapor.rawValue // Vapor

enum Language:Double {
    case html = 5.0
    case css = 3.0
    case php = 8.1
    case swift = 5.4
}

let type = Language(rawValue: 5.0)
let type2 = Language(rawValue: 5.1)

print(type)  // html
print(type2) // nil

enum Guitar {
    case maker(String) // メーカー
    case string(Int)  //  弦数
    case pickup(String)  // ピックアップの種類
}
var guitar = Guitar.maker("Fender")
guitar = . string(6)

struct Article {
    var title:String
    var category // ここを何で定義する？
    var body:String
}

struct Article {
    var title:String
    var category:Int // 1=HTML,2=CSS,3=PHP,4=Swiftとしておく
    var body:String
}

let data = Article(title: "記事１", category: 1, body: "内容")

struct Article {
    var title:String
    var category:String // 文字列で都度指定する
    var body:String
}

let data = Article(title: "記事１", category: "HTML", body: "内容")

enum Language {
    case HTML
    case CSS
    case PHP
    case Swift
}

struct Article {
    var title:String
    var category:Language
    var body:String
}

let data = Article(title: "記事１", category: .HTML, body: "内容")

switch data.category {
    case .HTML:
        print("HTMLだよ")
    case .CSS:
        print("CSSだよ")
    case .PHP:
        print("PHPだよ")
    case .Swift:
        print("Swiftだよ")
}

enum Language:String,CaseIterable {
    case HTML
    case CSS
    case PHP
    case Swift
}

print(Language.allCases)
// [__lldb_expr_1.Language.HTML, __lldb_expr_1.Language.CSS, __lldb_expr_1.Language.PHP, __lldb_expr_1.Language.Swift]