Swift字符串

<1>创建空字符串

let str1: String = ""

let str2: String = String()

<2>创建赋初值的字符串

var str3 = "helloworld-ZJP"

var str4 = String("你好")

<3>判断字符串是否为空

if str3.isEmpty {

    print("空值")

}

if str3.count == 0 {

    print("空值")

}