Swift 列表
阐述
列表是同类元素的有序集合，类型是 [T]。支持的操作为
- 创建
- 连接
- 索引
- 更改
- 遍历
实例
创建
创建时可以用字面值、构造函数或者两个列表相加：
var threeDoubles = Array(repeating: 0.0, count: 3)
var shoppingList = ["Eggs", "Milk"]
var anotherThreeDoubles = Array(repeating: 2.5, count: 3)
// anotherThreeDoubles is of type [Double], and equals [2.5, 2.5, 2.5]
var sixDoubles = threeDoubles + anotherThreeDoubles
// sixDoubles is inferred as [Double], and equals [0.0, 0.0, 0.0, 2.5, 2.5, 2.5]
索引
索引可以用来读写：
var firstItem = shoppingList[0]
shoppingList[0] = "Six eggs"
shoppingList[4...6] = ["Bananas", "Apples"]
遍历
for item in shoppingList {
print(item)
}
for (index, value) in shoppingList.enumerated() {
print("Item \(index + 1): \(value)")
}