The Swift Programming Language-官方教程精译Swift（5）集合类型 -- Collection Types

1 var shoppingList: String[] = ["Eggs", "Milk"] 
2 // shoppingList 已经被构造并且拥有两个初始项。

1 var shoppingList = ["Eggs", "Milk"] 

1 println("The shopping list contains \(shoppingList.count) items.") 
2 // 打印出"The shopping list contains 2 items."（这个数组有2个项） 

1 if shoppingList.isEmpty { 
2     println("The shopping list is empty.") 
3 } else { 
4     println("The shopping list is not empty.") 
5 } 
6 // 打印 "The shopping list is not empty."（shoppinglist不是空的） 

1 shoppingList.append("Flour") 
2 // shoppingList 现在有3个数据项，有人在摊煎饼 

1 shoppingList[0] = "Six eggs" 
2 // 其中的第一项现在是 "Six eggs" 而不是 "Eggs" 

1 shoppingList.insert("Maple Syrup", atIndex: 0) 
2 // shoppingList 现在有7项 
3 // "Maple Syrup" 现在是这个列表中的第一项 

1 let mapleSyrup = shoppingList.removeAtIndex(0) 
2 //索引值为0的数据项被移除 
3 // shoppingList 现在只有6项，而且不包括Maple Syrup 
4 // mapleSyrup常量的值等于被移除数据项的值 "Maple Syrup" 

1 for item in shoppingList { 
2     println(item) 
3 } 
4 // Six eggs 
5 // Milk 
6 // Flour 
7 // Baking Powder 
8 // Bananas 

1 for (index, value) in enumerate(shoppingList) { 
2     println("Item \(index + 1): \(value)") 
3 } 
4 // Item 1: Six eggs 
5 // Item 2: Milk 
6 // Item 3: Flour 
7 // Item 4: Baking Powder 
8 // Item 5: Bananas 

1 var someInts = Int[]() 
2 println("someInts is of type Int[] with \(someInts。count) items。") 
3 // 打印 "someInts is of type Int[] with 0 items。"（someInts是0数据项的Int[]数组） 

1 someInts.append(3) 
2 // someInts 现在包含一个INT值 
3 someInts = [] 
4 // someInts 现在是空数组，但是仍然是Int[]类型的。

1 var threeDoubles = Double[](count: 3, repeatedValue:0.0) 
2 // threeDoubles 是一种 Double[]数组, 等于 [0.0, 0.0, 0.0] 

1 var anotherThreeDoubles = Array(count: 3, repeatedValue: 2.5) 
2 // anotherThreeDoubles is inferred as Double[], and equals [2.5, 2.5, 2.5] 

1 var sixDoubles = threeDoubles + anotherThreeDoubles 
2 // sixDoubles 被推断为 Double[], 等于 [0.0, 0.0, 0.0, 2.5, 2.5, 2.5] 

1 [key 1: value 1, key 2: value 2, key 3: value 3]  

1 var airports: Dictionary<String, String> = ["TYO": "Tokyo", "DUB": "Dublin"] 

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

1 println("The dictionary of airports contains \(airports.count) items.") 
2 // 打印 "The dictionary of airports contains 2 items."（这个字典有两个数据项） 

1 if let oldValue = airports.updateValue("Dublin Internation", forKey: "DUB") { 
2     println("The old value for DUB was \(oldValue).") 
3 } 
4 // 打印出 "The old value for DUB was Dublin."（dub原值是dublin） 

1 if let airportName = airports["DUB"] { 
2     println("The name of the airport is \(airportName).") 
3 } else { 
4     println("That airport is not in the airports dictionary.") 
5 } 
6 // 打印 "The name of the airport is Dublin INTernation."（机场的名字是都柏林国际） 

1 if let removedValue = airports.removeValueForKey("DUB") { 
2     println("The removed airport‘s name is \(removedValue).") 
3 } else { 
4     println("The airports dictionary does not contain a value for DUB.") 
5 } 
6 // 打印 "The removed airport‘s name is Dublin International."（被移除的机场名字是都柏林国际） 

1 for (airportCode, airportName) in airports { 
2     prINTln("\(airportCode): \(airportName)") 
3 } 
4 // TYO: Tokyo 
5 // LHR: London Heathrow 

 1 for airportCode in airports.keys { 
 2     prINTln("Airport code: \(airportCode)") 
 3 } 
 4 // Airport code: TYO 
 5 // Airport code: LHR 
 6  
 7 for airportName in airports.values { 
 8     prINTln("Airport name: \(airportName)") 
 9 } 
10 // Airport name: Tokyo 
11 // Airport name: London Heathrow 

1 var namesOfIntegers = Dictionary<Int, String>() 
2 // namesOfIntegers 是一个空的 Dictionary<Int, String>