The Switf programming Language 練習代碼(6)

//

//  main.swift

//  classTest

//

//  Created by 小強 on 15/12/8.

//  Copyright © 2015年 小強. All rights reserved.

//

// 字典

var airports = ["TYO": "Tokyo", "DUB": "Dublin"];

print(airports);

// 讀取和修改字典

print("The dictionary of airport contains \(airports.count) items");

// 使用一個適合類型的 Key 做爲下標索引

airports["DUB"] = "London";

print(airports);

if let oldValue = airports.updateValue("Dublin Internation", forKey: "DUB")

{

    print("The old value for DUB was \(oldValue).");

}

print(airports);

//  使用下標語法來在字典中檢索特定的鍵對應的值

if let airportName = airports["DUB"]{

    

    print("The name of the airport is \(airportName).");

    

} else {

    

    print("That airport is not in the airports dictionary");

    

}

// 經過使用下標語法來經過給某個鍵的對應值賦值爲 nil 來從字典裏移除一個鍵值對

airports["DUB"] = nil;

print(airports);

airports["DUB"] = "Dublin";

print(airports);

// 使用removeValueForKey 方法移除鍵值對

if let removeValue = airports.removeValueForKey("DUB"){

    

    print("The removed airport's name is \(removeValue).");

    

} else {

    

    print("The airports dictionary does not contain a value for DUB.");

    

}

print(airports);

for (airportCode, airportName) in airports{

    

    print("airportCode = \(airportCode): airportName = \(airportName)");

    

}

for airportCode in airports.keys {

    

    print("Airport code: \(airportCode)");

    

}

var namesOfIntegers = Dictionary<Int, String>();

namesOfIntegers[16] = "sixteen";

print(namesOfIntegers);

// 使用 for-in 循環來遍歷一個集合中的全部元素

for index in 1 ... 5{

    

    print("\(index) times 5 is  \(index * 5)");

}

let base = 3;

let power = 10;

var answer = 1;

for _ in 1 ... power{

    

    answer *= base;

    

}

print("\(base) to the power of \(power) is \(answer).");

// 值綁定

let anotherPoint = (0, 3);

switch anotherPoint {

    

case (let x, 0):

    print("on the x-axis with an x value of \(x).");

case (0, let y):

    print("on the y-axis with a y value of \(y).");

case let (x, y):

    print("somewhere else at (\(x), \(y)).");

    

}

// case 塊的模式能夠使用 where 語句來判斷額外的條件

let yetAnotherPoint = (1, -1);

switch yetAnotherPoint {

    

case let (x, y) where x == y:

    print("(\(x),\(y)) is on the line x == y");

case let(x, y) where x == -y:

    print("(\(x),\(y)) is on the line x == -y");

case let (x, y):

    print("(\(x),\(y)) is just some arbitrary point");

    

}

let integerToDescripe = 5;

var description = "The number \(integerToDescripe) is "

endSwitch: switch integerToDescripe{

    

case 2, 3, 5, 7, 11,17, 19:

    description += "a prime number, and also";

    break endSwitch;

default:

    description += " an integer."

}

print(description);