【SWIFT】ランダムパスワード生成の演習(#46)

Udemy SWIFT by Angela – Code Exercise 4

ここ数日間、Udemy Swiftコースのレッスン46を終えた後の演習4と格闘しています。とりあえず7割くらいは理解したので、次に進もうと思います。

演習4：アルファベット26文字を元にランダムに6文字のパスワードを生成する。

いろんな書き方があるので、まとめていきます。初級的な書き方（長いコード）から上級的な書き方（短いコード）の順番になっています。

方法1：直感的な書き方（10行）

let alphabet = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]
    
let p1 = alphabet [Int.random(in: 0 ... 25)]
let p2 = alphabet [Int.random(in: 0 ... 25)]
let p3 = alphabet [Int.random(in: 0 ... 25)]
let p4 = alphabet [Int.random(in: 0 ... 25)]
let p5 = alphabet [Int.random(in: 0 ... 25)]
let p6 = alphabet [Int.random(in: 0 ... 25)]
    
var password = p1 + p2 + p3 + p4 + p5 + p6
print (password)

方法2：randomElementを使う（10行）

let alphabet = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]
        
var p1 = alphabet.randomElement()!
var p2 = alphabet.randomElement()!
var p3 = alphabet.randomElement()!
var p4 = alphabet.randomElement()!
var p5 = alphabet.randomElement()!
var p6 = alphabet.randomElement()!

var password = p1 + p2 + p3 + p4 + p5 + p6
print(password)

メリット：配列の値の数量を気にしなくてよい

注意点：最後に「！」マークが必要。これがないと6つとも同じ文字になる。

方法3：randomElement + 複合演算子（7行）

let alphabet = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]
    
var password = ""
while password.count < 6 {
password += alphabet.randomElement()!
}
print(password)

関連記事：+= の意味

複合演算子は数字に使いますが、Stringにも使えます。

ただし、1+2=3のにたいして、”a”+”b”=”ab”になります。

方法4：randomElement + for + terminator（5行）

let alphabet = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]

for _ in 1...6 {
print(alphabet.randomElement()!, terminator: "");
}

これは46レッスンまでしか学んでない私にとっては難解ですが、ちゃんと作動しました。

説明できるようになったら、また戻ってきて解説を追記します。

Udemyオフィシャルの答えとみんなの討論はこちら

ではまた。