Created
December 2, 2014 04:53
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Swift勉強会#2
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// Playground - noun: a place where people can play | |
import UIKit | |
//Optional型 | |
//Optionalとはnilの代入を許すこと | |
//Optionalにするには?をつけてwrapする。 | |
var a : Int = 3 | |
var b : Int? = 2 | |
var c : Int? = 20 | |
//a = nil//これはエラーになる | |
b = nil//これはOK | |
//Optional型を使うときは!をつけてunwrapする | |
a+30 | |
//c+20//これはエラー | |
c!+20//これはOK | |
//なんでもOKなAny型というものもある | |
//AnyはOptional | |
var x: Any = "hoge" | |
var y: Any = 30 | |
//Any型を実際に使うときは型変換してからやる | |
// 型変換 | |
var i = x as? Int//ダウンキャストできないのでnil | |
i = y as? Int | |
// for文 | |
for var i=10; i<=20; i++ { | |
if i%7 == 0 { | |
println ("\(i) can be divided by 7") | |
} | |
} | |
var fruits_color : Dictionary = [ | |
"apple" : "red", | |
"grape" : "purple", | |
"banana" : "yellow" | |
] | |
for (name, color) in fruits_color { | |
println ("\(name) は \(color)") | |
} | |
//switch文 | |
var sw_number: Int = 1 | |
switch(sw_number){ | |
case 0...9://0~9 | |
println("1桁") | |
case 10..<100://100は含まない | |
println("2桁") | |
default: | |
println("その他") | |
} | |
//関数 | |
func calcSum(minNum:Int, maxNum:Int) -> Int { | |
var sum : Int = 0 | |
for number in minNum...maxNum { | |
sum += number | |
} | |
return sum | |
} | |
calcSum(2,5) | |
//演習問題1 | |
//引数にmax(Int)を指定し、1からmaxまでの2の倍数の合計値を返すメソッドを作る | |
func practice_1(max:Int) -> Int { | |
var sum = 0 | |
for number in 1...max { | |
if(number%2 == 0) { | |
sum += number | |
} | |
} | |
return sum | |
} | |
practice_1(30)//240 |
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