Swift 2 学习笔记 6.数组

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数组:有序的数据集合

• 数组的初始化

var numbers: [Int] = [0,1,2,3,4,5]
var vowels: [String] = ["A","E","I","O","U"]

var emptyArray1: [Int] = []
var emptyArray2: Array<Int> = []
var emptyArray3 = [Int]()
var emptyArray4 = Array<Int>()

var allZero = [Int](repeating: 0, count: 5)

• 数组的基本用法 --> Swift4

var numbers: [Int] = [0,1,2,3,4,5]
var vowels: [String] = ["A","E","I","O","U"]
var emptyArray: [Int] = []

numbers.count  // 5
vowels.isEmpty  // false
numbers[2]  // 3
numbers.first  // 1
emptyArray.first  // nil
numbers.min()  // 1
vowels.max()  // "U"
numbers[2..<4]  // [3,4]
vowels.contains("A")  // true
vowels.firstIndex(of: "E")  // 1
for (index, vowel) in vowels.enumerated() {
    print("\(index):\(vowel)")
}

• 数组的更多用法 --> Swift4

var numbers: [Int] = [1,2,3,4,5]
numbers.append(6)  // [1,2,3,4,5,6]
numbers += [7]  // [1,2,3,4,5,6,7]
numbers.insert(0, at: 0)  // [0,1,2,3,4,5,6,7]
numbers.removeLast()  // [0,1,2,3,4,5,6]
numbers.removeFirst()  // [1,2,3,4,5,6]
numbers.remove(at: 2)  // [1,2,4,5,6]
numbers.removeSubrange(1...2) // [1,5,6]
numbers[0] = 0  // [0,5,6]
numbers[0...1] = [0]  // [0,6]
numbers.removeAll()  // []

• 二维数组

var board = [ [0,1], [0,1,2], [0,1,2,3] ]
board[0]  // [0,1]
board[0][0]  // [0]
board.count  // 3
board[0].count  // 2
board.append([0])  // [ [0,1], [0,1,2], [0,1,2,3], [0] ]
board[0].append(2) // [ [0,1,2], [0,1,2], [0,1,2,3], [0] ]
board += [ [0] ]  // [ [0,1,2], [0,1,2], [0,1,2,3], [0], [0] ]