數組
- 1.創建數組
let someInts:[Int] = [] //創建一個類型為Int的空數組
var someInts1 = [Int](repeating: 10, count: 15) //創建一個類型為Int,數量為3，初始值為10的空數組
var someInts2:[Int] = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15] //直接填寫數據創建數組
var someString:[String] = ["aa","bb"] //創建一個數組類型的
let someString1 = Array(repeating: 2.5, count: 3) - 2.讀取數組中數據的數量
print(someInts1.count) - 3.判斷數組是否為空
print(someInts.isEmpty)
print(someInts2.isEmpty) - 4.數組后面 添加新的數據項
someString.append("shuiguo")
someString += ["cc","ee","dd","gg","ff","dd"] - 5.獲取數據中的數據項
print(someInts1[0])
print(someInts1[1]) - 6.修改已有索引對應的數據值
someInts2[0] = 20
// 可以利用下標一次改變一系列數據值
someString[1...6] = ["胡椒","辣椒"] - 7.insert 在某個具體索引值之前添加數據項
someInts2.insert(4, at: 0) - 8.remove 在某個具體位置，刪除數據項
someInts2.remove(at: 10)
someInts2.removeLast()
someInts2.removeFirst()
// 刪除后面4個
someInts2.removeLast(4)
數組的遍歷
for item in someInts2 {
print(item)
}
for index in someInts2.enumerated() {
print("Item \(index.element) : \(index.offset) \(index)")
}
- 倒序遍歷
for index in someInts2.reversed() {
print(index)
} - 倒序下標遍歷
for index in someInts2.reversed().enumerated() {
print("Item (index.element) : (index.offset) (index)")
}
