//自動(dòng)類(lèi)型推斷 var 定義變量
var str = "Hello, playground"
//let 定義常量（不能修改的量）
let name="Hello,playground"
2.數(shù)據(jù)類(lèi)型定義
//字符串
let name1:String = "Lanou"
//字符
let gender : Character = "M"
//整型
let age : Int = 12
//浮點(diǎn)型
let height : Float = 12.2
//雙精度浮點(diǎn)型
let height1 : Double = 12.222
3.字符串的操作
//長(zhǎng)度
let length = name.characters.count
// 拼接
var name3 : String = name + "pin\(123)jie"
print("name=\(name3)")
//獲取第幾個(gè)位置
let index=name3.index(name3.startIndex,offsetBy:2)
//rang(取字符串中指定位置的值)
let student = "yangshaofeng"
let startIndex = student.index(student.startIndex,offsetBy:2)
let endIndex=student.index(student.endIndex,offsetBy:-2)
let rang = startIndex..<endIndex
student.substring(with:rang)
//插入的上面獲取的位置
name3.insert(contentsOf: "charu".characters, at: index)
// 遍歷
for item in name3.characters{
print(item)
}
//切割
var school = "jiningshifan"
let index1 = school.index(school.startIndex,offsetBy:2)
let newSchool=school.substring(to: index1)
print(newSchool)
4.數(shù)組操作
//定義數(shù)組
var arr = [1,2,3]
var arr1 : [Int] = [Int]()
//增加元素
arr1.append(2)
//刪除元素
let element = arr1.remove(at: 0)
//更新元素
arr[1] = 22
print(arr)
// 遍歷
for item in arr {
print(item)
}
for item in 0..<arr.count {
print(arr[index])
}
for (index,item) in arr.enumerated(){
print("index=\(index) item=\(item)
}
